this is a thinking cap problem...

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1993 lincoln T.C. 4.6L. runs fine until symptom appears.
happens on interstate speeds.
it has been on cruise control for about an hour. the engine will go to
stumbling and missing, but will idle nicely, if you come to a stop on the side of the road. when calling for power like in acceleration, it will miss badly. at first, one will think it is the fuel system, but this has been ruled out already.
now, i'm looking at the engine's ignition management system.
it appears to be a temperature related problem because if you let the car cool off for a few minutes, it will run great until 15 to 20 minutes down the road and the same symptoms appear.
logic tells me that there's a computer in the ignition system that is having something opening up and it is dropping the system down into to run in the "fall safe" mode.
i just wonder if anyone has had this happen to them and can tell me where to look at the found the guilty module. x-ray diagnosis didn't turn up anything.
thanks,
~ curtis
another hint - on board computer shows the overall gas mileage will drop from 23 miles to gallon to 12 when symptom happens.
knowledge is power - growing old is mandatory - growing wise is optional "Many more men die with prostate cancer than of it. Growing old is invariably fatal. Prostate cancer is only sometimes so." http://community.webtv.net/PALMER_ENT/doc
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c palmer wrote:

No real mystery. Your OEM plug wires are going bad and/or you have Bosch plugs and aftermarket plug wires installed. If OEM they're 13 yeaes old. These cars don't like Bosch plugs and eat aftermarket wires for lunch. A failing coil pack is a possibility but it is more commonly the plugs or wires.
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No real mystery. Your OEM plug wires are going bad and/or you have Bosch plugs and aftermarket plug wires installed. If OEM they're 13 yeaes old. These cars don't like Bosch plugs and eat aftermarket wires for lunch. A failing coil pack is a possibility but it is more commonly the plugs or wires. ======hi tom - thanks for the input, but here's the update...
OEM wires were replaced (with ford wires) and have less than 15,000 miles. doesn't have bosch plugs, went back the original brand.
the car runs flawlessly for that hour or so, and then the symptom appears, if problem were to happen with wires or plugs, it would usually show up either when they are cold or somewhere during that first hour of driving or under full load condition sometimes. i don't even have a hint of lack of performance during that first hour.
i've not had a coil pack go bad before, so i'm lost on that one. my question would be - doesn't a coil pack have one cylinder not firing correctly? when the symptom appears, it doesn't have a repeating dead end, but a sputter type response, similar to a lack of fuel and then, it might hit on all eight cylinders for a 1/2 mile or so, but the key to the symptom seems to be that if you try to push the engine down the road after the symptoms appear, the more you feel like you might be pushing the car in another mile are so, because the symptoms, just keep getting worse to where it has no power to pull itself, like up a hill. for example, one event, i was traveling at 75 mph, but by the time, i was at the top of the hill, it was down to 43 and that was not of cruise control but feathering the throttle trying to get the every bit of power i could out of the engine.
i pulled off to the side of the road within a 1/2 mile of this event and the running was purring like nothing was wrong. put it in gear and call for power and it feels like it wants to stall and will buck and snort. turn the engine off, wait a few minutes and the engine runs great again with lots of power.
~ curtis
knowledge is power - growing old is mandatory - growing wise is optional "Many more men die with prostate cancer than of it. Growing old is invariably fatal. Prostate cancer is only sometimes so." http://community.webtv.net/PALMER_ENT/doc
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Just a thought but you could have a faulty EGR or related plumbing.
Gerald
c palmer wrote:

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If you haven't replaced the fuel filter lately do it now and let us know what happens. Bob
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c palmer wrote:

Very smart move. 4.6s like Bosch plugs and cheap plug wires about as much as a 4 year old likes spinach and lima beans.
With the extra info, Yep, that's a head scratcher. That hour of good performance throws me. There's 2 things that come to mind for your symptoms, but they don't seem the fit the conditions that you describe exactly. First, pull the plug wires and apply a liberal amount of dielectric grease to the boots then drive it to see if there is any change. Then, clean the element on the MAF sensor with a non residual solvent, see if that changes anything. Obviously check the fuel pressure when the symptoms occour, but I wouldn't expect to see a large drop in fuel economy if the engine is not getting enough fuel to start with. I recall hearing something about flaky Crank Position Sensor connections being common on these motors but I don't remember the details.
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Interesting that you'd mention timing. Except for the part about it taking an hour to happen, doesn't this sound like a timing problem: An extreme lack of power, falls on its face under load, yet idles fine.
The only other thing not mentioned that might explain it all is a bad catalytic converter.
CJB
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Tom Adkins wrote:

No codes even when it misses badly? hmmmm. 15K on the plugs and wires isn't exactly new. Im with Tom. Have you even looked at the wires, pulled them out of those deep, water and gunk collector holes they're in? Its amazing how a 4.6 can kill wires and plugs. Did you use the 32pp plugs?(iirc) Start with the basics :)Someone mentioned a crank sensor. I've seen them cause a no start but not a miss on a cv but you never know....Try to get it to set a miss code....or some code :)
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I only have guesses... In old cars, this sounds like a pickup coil or ballast resistor. It also sounds like the symptoms in my neighbors 91 bronco, his ignition module died. It's mounted on his distributor, which gets hotter as the car runs.
On Sat, 15 Apr 2006 17:56:17 -0500, PALMER snipped-for-privacy@webtv.net (c palmer) wrote:

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Have the codes read out. Then come back with them. Codes, not definitions
PALMER snipped-for-privacy@webtv.net (c palmer) wrote:

--
Yeh, I'm a Krusty old Geezer, putting up with my 'smartass' is the price
you pay..DEAL with it!
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Here's another thought:
1. Get a can of 'circuit cooler', locate all suspect modules, then when it happens.. spray them (heat sink not the plastic) and see what one affects and what one doesnt
2. When it happens, go back and vent the gas tank.. tighten it back and try immediately
PALMER snipped-for-privacy@webtv.net (c palmer) wrote:

--
Yeh, I'm a Krusty old Geezer, putting up with my 'smartass' is the price
you pay..DEAL with it!
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probably the easiest way to answer these responses is in one message....
======
From: snipped-for-privacy@yahoo.com (gerald2003r) Just a thought but you could have a faulty EGR or related plumbing. Gerald ------- hi gerald - had typical EGR problem long time ago. fixed it, not had problem since. on related plumbing - all rubber tubing that collapses for ford's poor design over time, (for example - the "t" connector and the driver's side hose behind engine have all been replaced. ========
From: snipped-for-privacy@privacy.org (Shel-hed) I only have guesses... In old cars, this sounds like a pickup coil or ballast resistor. It also sounds like the symptoms in my neighbors 91 bronco, his ignition module died. It's mounted on his distributor, which gets hotter as the car runs.
---------- hi shel-hed - on the 4.6L, it doesn't have a distributor, or ballast resistor - so that rules out the common problem that ford had on what you described. but that would have been one of the things i would have jumped on had the engine had a distributor.
========== From: snipped-for-privacy@yaywho.com (BackyardMechanic) Have the codes read out. Then come back with them. Codes, not definitions
hi backyard - no codes are coming out - that's the problem. that's the head scratcher......
Here's another thought: 1. Get a can of 'circuit cooler', locate all suspect modules, then when it happens.. spray them (heat sink not the plastic) and see what one affects and what one doesnt -----> i hadn't done that yet and had gave it some thought, but i will probably have to carry it in the car and perform road side troubleshooting when this happens. was hoping that someone had ran into this problem from the symptoms i was describing.
2. When it happens, go back and vent the gas tank.. tighten it back and try immediately
------> tried that the first, second, and third time it happened. made no difference.
thanks for all the input so far. i really do appreciate it.
i've had some real hair pullers in my time and they usually end up one of two ways. 1. the "wow!" i could have had a V-8. so simple and it's one of those slam yourself on the forehead type solutions.
2. the bastard case. you happen to just catch it at the right time and were standing at the right place. any other time, it doesn't show up.
~ curtis
knowledge is power - growing old is mandatory - growing wise is optional "Many more men die with prostate cancer than of it. Growing old is invariably fatal. Prostate cancer is only sometimes so." http://community.webtv.net/PALMER_ENT/doc
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(Backyard Mechanic) Have the codes read out. Then come back with them. Codes, not definitions
hi backyard - no codes are coming out - that's the problem. that's the head scratcher......
Here's another thought: 1. Get a can of 'circuit cooler', locate all suspect modules, then when it happens.. spray them (heat sink not the plastic) and see what one affects and what one doesnt -----> i hadn't done that yet and had gave it some thought, but i will probably have to carry it in the car and perform road side troubleshooting when this happens. was hoping that someone had ran into this problem from the symptoms i was describing.
2. When it happens, go back and vent the gas tank.. tighten it back and try immediately
------> tried that the first, second, and third time it happened. made no difference.
thanks for all the input so far. i really do appreciate it.
i've had some real hair pullers in my time and they usually end up one of two ways. 1. the "wow!" i could have had a V-8. so simple and it's one of those slam yourself on the forehead type solutions.
2. the bastard case. you happen to just catch it at the right time and were standing at the right place. any other time, it doesn't show up.
~ curtis
knowledge is power - growing old is mandatory - growing wise is optional "Many more men die with prostate cancer than of it. Growing old is invariably fatal. Prostate cancer is only sometimes so." http://community.webtv.net/PALMER_ENT/doc
Is vapor lock unheard of in fuel injected engines?
Richard
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If it were me I would go for the coil pack, BUT before I did that I would disconnect the battery for 10 minutes or so to lose anything stored in the computer. Maybe look at the coil pack electrical feed connections? I don't know the design of the coil pack enough and it would be interesting if someone here could speak about it to say if the 1993 series coil packs are one as a unit of if they will fail seperatly per cylinder? When it comes to engine management I think computer... Disconect that Battery and see what happens first... The computer is also going to tell the injectors when to fire. I understand the heat failure idea but I'm thinking the computer forgot what to do idea is also plausable. Worth a shot...
Happy Easter..
Gerald
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PALMER snipped-for-privacy@webtv.net (c palmer) wrote:

IOW, you are saying you KNOW you have proper fuel pressure AT THE TIME the Engine is running badly.
Hate to be a poopy-head.... but you DONT call a consultant into your business to solve a problem and tell him the obvious has been ruled out without reviewing it.
--
Yeh, I'm a Krusty old Geezer, putting up with my 'smartass' is the price
you pay..DEAL with it!
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bob wrote - If you haven't replaced the fuel filter lately do it now and let us know what happens.
---------> fuel pump and filter both replaced about six months ago.
before fuel pump and filter were replaced - the engine did have one episode similar to what i'm describing about 9 months after about 2 hours of interstate driving, but i was close to home when it was acting up and was going to work on it later that day but problem went away, so didn't give much thought. now, it seems to be back and a lot more frequently, and with a new pump and filter in place.
======== From: snipped-for-privacy@yaywho.com (BackyardMechanic) PALMER snipped-for-privacy@webtv.net (c palmer) wrote: at first, one will think it is the fuel system, but this has been ruled out already.
IOW, you are saying you KNOW you have proper fuel pressure AT THE TIME the Engine is running badly. Hate to be a poopy-head.... but you DONT call a consultant into your business to solve a problem and tell him the obvious has been ruled out without reviewing it.
-------> don't worry about being a poopy -head, i'll take any ideas and leads. :))
you are right, i didn't have a fuel gauge with me at the time it was acting up. but, what puts a spin on this problem is that i have been able to put it in neutral, kill the engine and coast almost a mile on a down grade. (thinking that the passing air would cool down the part or module) when the speed drops down to where traffic is passing me, i can start the engine and it runs great. have even taken on the next steep hill under full throttle delivery figuring that if it is a fuel delivery problem, holding the engine's feet to the fire for a longer duration than what one takes to pass, should show up something - if it was fuel related, but the engine hung in there and kept delivering the power with no miss or stubble.
=============
From: snipped-for-privacy@yahoo.com (gerald2003r)
Is vapor lock unheard of in fuel injected engines?
------->i, personally, haven't heard of a fuel injected engine vapor locking. =======
If it were me I would go for the coil pack, BUT before I did that I would disconnect the battery for 10 minutes or so to lose anything stored in the computer. Maybe look at the coil pack electrical feed connections? I don't know the design of the coil pack enough and it would be interesting if someone here could speak about it to say if the 1993 series coil packs are one as a unit of if they will fail separately per cylinder? When it comes to engine management I think computer... Disconect that Battery and see what happens first... The computer is also going to tell the injectors when to fire. I understand the heat failure idea but I'm thinking the computer forgot what to do idea is also plausible. Worth a shot...
==========
-------> the coil pack design are four to a side - up front. they don't get the heat as they would if they were installed on the back side of the engine or in the case of the 1998 and up with the coil over plug design, where heat is a common problem in killing the module.
the check engine light does comes on, but it is a soft core error, and the computer resets itself, when the key is turned off.
i haven't been able to get to anywhere to pull the codes when the check engine light comes on. just seems that i'm at the wrong place at that particular time. along with the can of "quick kool", i should bring my x-ray hook up unit too.
--------- From: snipped-for-privacy@remove.comcast.net (TomAdkins)
With the extra info, Yep, that's a head scratcher. That hour of good performance throws me. There's 2 things that come to mind for your symptoms, but they don't seem the fit the conditions that you describe exactly. First, pull the plug wires and apply a liberal amount of dielectric grease to the boots then drive it to see if there is any change. Then, clean the element on the MAF sensor with a non residual solvent, see if that changes anything. Obviously check the fuel pressure when the symptoms occur, but I wouldn't expect to see a large drop in fuel economy if the engine is not getting enough fuel to start with. I recall hearing something about flaky Crank Position Sensor connections being common on these motors but I don't remember the details.
============
--------> anything is possible when it comes to mechanics, that's for sure. but the plug wires are fairly new. i just pulled them after i read your post and the boots are still good and soft, with no evidence of carbon tracking.
the reason i replaced them was because it did have a repeated misfiring (common for plugs and wires) and it did fix the problem right away and it was permanent.
with the MAF sensor, i don't think would keep resetting itself. by that, i'm referring to where the engine, goes right back up to the 23 - 25 mpg range after the problem resolves itself. that is, until, the symptoms show it and then, the computer's overall mileage - after reset - will show 12 - 13 mpg while the engine is acting up.
i'm not aware of how the flaky crankshaft sensors are suppose to behave when they are going out. unless my thinking is off, i'm thinking that when the engine doesn't get the crankshaft sensor input, it just doesn't fire. this engine fires, but sputters-like and i have to keep in mind that it still idles great when these symptoms are going on, just can't call for power from the engine when it is in this state. another head scratcher.
--------------- maybe, i'm just getting too old for this stuff and they can just hook it up to another computer and let the two computers talk to each other. i know in time, the part will fail and then it's easy to find, but i don't want to be miles from home. wife has had two heart attacks, plus two partly stopped up stents and i've got two different cancers chewing on me and bum knees. so neither one of us don't need be walking on the interstate, especially, if you know that something is not quite right under the hood. i use the car a lot to go the VA hospital in the next state over for treatments and follow up visits. that might explain why a lot of interstate driving.
~ curtis
knowledge is power - growing old is mandatory - growing wise is optional "Many more men die with prostate cancer than of it. Growing old is invariably fatal. Prostate cancer is only sometimes so." http://community.webtv.net/PALMER_ENT/doc
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Easy... You are on the right track and you have allot of peoples attention... Slow down... You did quote me as being on the "Vapor Lock trail" ... Not with Injection... Count me out of that... Don't worry I know it was just a mis quote. Disconnect the battery! ... 10 minutes and then quote me ok... Smile... Happy Easter...
Gerald
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Wires/plugs?
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look to see if the last person to do an oil change missed the fill hole in the valve cover and dumped oil down the intake. if he did, the oil will fill the plug holes, and short out the wires, causing a noncode miss on acceleration. i have seen this 3 times now.
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From: snipped-for-privacy@yahoo.com (gerald2003r)
Easy... You are on the right track and you have allot of peoples attention... Slow down... You did quote me as being on the "Vapor Lock trail" ... Not with Injection... Count me out of that... Don't worry I know it was just a mis quote. Disconnect the battery! ... 10 minutes and then quote me ok... Smile... Happy Easter... Gerald ----- hi gerald - i've should have mentioned that was one of the first things that i did back when i noticed this symptom. i call it clearing the pad. that way if anything shows up, you know for a fact, it was after that point in time. i really do appreciate your input.
============ From: snipped-for-privacy@optonline.net (Tom)
look to see if the last person to do an oil change missed the fill hole in the valve cover and dumped oil down the intake. if he did, the oil will fill the plug holes, and short out the wires, causing a noncode miss on acceleration. i have seen this 3 times now.
--------- hi tom - i've always performed the maintenance of my vehicles for the past 45 years. and you are right about some of the things that can happen when people get there oil changed. but the joker in this particular deck is that it runs just fine for some time and then, wham!!!! it acts up, let it sit, and it runs great again - without anybody touching it. that is why i think it is heat related problem.
============From: snipped-for-privacy@earthlink.net (Repairman)
You need a fuel pressure tester on the rail when it acts up, had a Taurus that drove me crazy that acted the same way. Fuel pump was heating up and losing pressure, would come back after sitting and cooling down. Putting fresh gas into the tank would cool the pump down and get me going again. Even though your pump is new it could be defective, fuel pressure tester is as important as a code reader nowadays.
-------
hi repairman - no argument about what you said. gauges do provide a lot of input. i don't know if they make a fuel pressure gauge that you can screw end and leave there. if not, i'll create something and when it happens, as you said, it will give me up to date information at that point when i open the hood.
========= From: snipped-for-privacy@excite.nospam (CJB) "Tom Adkins"
Interesting that you'd mention timing. Except for the part about it taking an hour to happen, doesn't this sound like a timing problem: An extreme lack of power, falls on its face under load, yet idles fine.
The only other thing not mentioned that might explain it all is a bad catalytic converter.
--------- hi tom - hate to rain on the parade on this one, but i can run the car under full throttle and it doesn't want to lug or even a hint that it has a back pressure on the exhaust. in fact, i ran the engine to the upper RPM's under full load to push the air flow through the pipes and couldn't see anything out of the ordinary. thanks for the input. it keeps me on my toes.
i guess i should mention that i've got a few mustang GT's and i'm use to performance. so, what this engine has done, it's so far out of the ordinary. runs great for a hour, then, wants to lay down and die, has got me to putting the thinking cap on.
~ curtis
knowledge is power - growing old is mandatory - growing wise is optional "Many more men die with prostate cancer than of it. Growing old is invariably fatal. Prostate cancer is only sometimes so." http://community.webtv.net/PALMER_ENT/doc
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