93 Ford Taurus GL 3.0 Liter V6 with Intermittent Rough Idle Problem

This issue has baffled me for over a month now and I am still no closer to discovering what's causing it.
I have a 93 Ford Taurus GL with a problem with rough idling (to the
point of stalling if gas is not applied to keep it at a high enough speed) and, of course, stalling. The problem has persisted after I've changed the fuel pump and fuel filter, the EGR valve, the Idle Air Control Valve and the spark plug cables. Code readouts point all over the place, if the car generates codes at all. Codes, when they are logged, point to a vacuum issue. The rough idle problem does not always start first thing.
In the mornings, I can sometimes run the car halfway to work before it misses a lick. Sometimes it can go all day and not miss a beat. And then there are some days I don't get out of the driveway.
There is a whistle when the engine is idling in the driveway but, in the location I hear the whistling, there are no vacuum hoses to be seen. So, if there is a vacuum leak, I can't locate it. Not only can't I locate it, it is beyond intermittent.
Performed a leak test around the intake manifold and there was no leaking there. I have even cleaned the carbon from the butterfly valve on the intake and it has not helped the problem any.
I'm nearing my wits end here and, if I take it into a mechanic, I'd like to point to something more specific than 'it has an intermittent problem, possibly related to the vacuum'. Any ideas or help that you can offere would be most appreciated.
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It would be nice if we knew the specific codes you read out. Never let Autozone tell you what they think the codes mean, and never ask for tech advice by telling the person you're consulting what YOU think the codes mean.
The PRIMARY function of the Idle Control Valve is to keep the engine running by giving it enough air. If it dies from low idle, it's not working right... and vacuum leaks result in a HIGH idle.
It's quite possible your new one is defective.. or you have a bad connection in the wiring betwen it and the PCM.
If you also had certain shifting problems, I'd suggest changing the TPS. For some reason EECIV doesnt tell you if that sensor is flaky.
I would pull the connectors for the IAC, TPS (probably okay to just change the TPS), etc and check for corrosion.. clean them and lube them with dielectric grease. Also check the engine to body ground and the harness ground near the PcM.
--
Yeh, I'm a Krusty old Geezer, putting up with my 'smartass' is the price
you pay..DEAL with it!
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These are the codes that the car produced yesterday on the drive into work (the first time the check engine light has come on and stayed on since we began putzing with the car with its current problem):
558 EGR Vacuum Regulator CKT (EVR) 565 Canister Purge CKT Fault 652 Modulated Lockup Solenoid CKT
157 MAF signal too low 211 PIP Erratic 332 EGR valve no opening (EVP/PFE/DPFE)
And these codes were read off of the Snap-On Code Reader that was borrowed from a mechanic friend up at work. Hope the codes are helpful and thank you very much for your suggestions.
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caliwolf wrote:

As a old taurus owner, i will suggest a few things:
Vacuum hoses. they tend to rot and leak. start with the hoses on the passenger side of the engine. Look closely for cracks. replace ALL hoses that look suspicious. there is a hose that plugs into a plastic hose that goes down to the front drivers side radiator area then turns into a rubber hose again (goes to purge). check the hoses in this area and replace as needed. Some of these hoses are hidden and have covers over them so so sleuthing is needed.
change the plug wires. clean in MAF sensor and clean out the IAT. change the fuel filter and air filter. Rescan and see where your at.
Bob
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I have the same problem with my 93 Taurus. Have run my Sunpro code scanner on it and it comes up with. *Code 53.TPI (Throttle Position Sensor)* *Voltage too high.* *Code 95 TAC (Thermactor Air System) * *Problem on right side air flow always upstream.* *or FPM (Fuel Pump Monitor)* *Indicates circuit problems.* *Code 3 EGO (Exhaust Gas Oxygen) sensor* *No switching (Right Side0 I'm not blaming the EGR valve til my stepson uses his big computer on it tomorrow. He thinks it might just be a sensor controling the EGR valve. * caliwolf;1787906 Wrote: > > > > It would be nice if we knew the specific codes you read out. Never > let > > Autozone tell you what they think the codes mean, > > and > > never ask for tech advice by telling the person you're consulting > what > > YOU think the codes mean. > > These are the codes that the car produced yesterday on the drive into > work (the first time the check engine light has come on and stayed on > since we began putzing with the car with its current problem): > > 558 EGR Vacuum Regulator CKT (EVR) > 565 Canister Purge CKT Fault > 652 Modulated Lockup Solenoid CKT > > 157 MAF signal too low > 211 PIP Erratic > 332 EGR valve no opening (EVP/PFE/DPFE) > > And these codes were read off of the Snap-On Code Reader that was > borrowed from a mechanic friend up at work. Hope the codes are helpful > and thank you very much for your suggestions.
--
lhasaluvers
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caliwolf wrote:

If there's not a vacuum line there, perhaps there should be? There should be a sticker with a graphic of the vacuum lines under the hood somewhere; I know there is on both of my Tauruses (Tauri?). I'd make sure you can account for all of them.

Personally, I'm reluctant to offer opinions on what a mechanic *should do* when I bring a car in for service. He may very willingly perform the procedure I've outlined, knowing full well that I'm just wrong. All it does is run my bill up. You may end up better off to tell him just the symptoms and mention that you hear a new hiss as well. Let him figure it out. If you don't trust him to do that, why are you there?
--
Mortimer Schnerd, RN
mschnerdatcarolina.rr.com
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As a update:
The issue is really more of a low idle than a rough one. Gas has to be applied, the idle gets so low. It becomes slobbery but I believe that's because of low idle.
While running down the highway, the engine 'surges', that is goes up and down in tone, as if the computer is trying to compensate for something.
Now, the car itself will crank and put out no spark; no spark from the plugs. It will not start at all. It put out the following fault codes, similar to the ones before:
564 Fan Control Fault 558 EGR Vacuum Regulator (EVR) Fault 565 Canister Purge Circuit Fault 652 Modulated Lockup Solenoid Circuit 625 Electronic Pressure Control Open.
It just keeps getting better and better....
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You have a serious PCM power problem.
Tha explains why the idle is low... and so many differnt ckt faults; not enough power to drive those various soleoids, etc.
Start checking all the engine and harness grounds and the CCRM {relay module}
--
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you pay..DEAL with it!
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I have just got about the same problem with mu 93 Taurus 3.0. When I first start it it will idle rough and stall. If I get it in drive or reverse right away, it smooths out and will run great. I used my Sunpro code scanner for it and got the following codes. *Code 53.TPI (Throttle Position Sensor)* *Voltage too high.* *Code 95 TAC (Thermactor Air System) * *Problem on right side air flow always upstream.* *or FPM (Fuel Pump Monitor)* *Indicates circuit problems.* *Code 3 EGO (Exhaust Gas Oxygen) sensor* *No switching (Right Side0 I was blaming the EGR but it might be another sensor. My stepson and I are going to check it with his big computer tomorrow. He's not sure it is the EGR valve too. I will post our findings here later. *
In the mornings, I can sometimes run the car halfway to work before it misses a lick. Sometimes it can go all day and not miss a beat. And then there are some days I don't get out of the driveway.
There is a whistle when the engine is idling in the driveway but, in the location I hear the whistling, there are no vacuum hoses to be seen. So, if there is a vacuum leak, I can't locate it. Not only can't I locate it, it is beyond intermittent.
Performed a leak test around the intake manifold and there was no leaking there. I have even cleaned the carbon from the butterfly valve on the intake and it has not helped the problem any.
I'm nearing my wits end here and, if I take it into a mechanic, I'd like to point to something more specific than 'it has an intermittent problem, possibly related to the vacuum'. Any ideas or help that you can offere would be most appreciated.
--
lhasaluvers
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caliwolf;1787902 Wrote: > This issue has baffled me for over a month now and I am still no closer > to discovering what's causing it. > > I have a 93 Ford Taurus GL with a problem with rough idling (to the > point of stalling if gas is not applied to keep it at a high enough > speed) and, of course, stalling. The problem has persisted after I've > changed the fuel pump and fuel filter, the EGR valve, the Idle Air > Control Valve and the spark plug cables. Code readouts point all over > the place, if the car generates codes at all. Codes, when they are > logged, point to a vacuum issue. The rough idle problem does not > always start first thing. > > In the mornings, I can sometimes run the car halfway to work before it > misses a lick. Sometimes it can go all day and not miss a beat. And > then there are some days I don't get out of the driveway. > > There is a whistle when the engine is idling in the driveway but, in > the location I hear the whistling, there are no vacuum hoses to be > seen. So, if there is a vacuum leak, I can't locate it. Not only > can't I locate it, it is beyond intermittent. > > Performed a leak test around the intake manifold and there was no > leaking there. I have even cleaned the carbon from the butterfly valve > on the intake and it has not helped the problem any. > > I'm nearing my wits end here and, if I take it into a mechanic, I'd > like to point to something more specific than 'it has an intermittent > problem, possibly related to the vacuum'. Any ideas or help that you > can offere would be most appreciated. *We finally found the right part to fix the problem by just pure luck. After getting all the different codes, my stepson decided to check out the Air Bypass Valve. He found that it was stuck in a half open position. We replaced the ABV and the car ran perfect. Ran code check again and had none. Another thing that was happening when the ABV was bad was the headlights would dim when you applied the brakes. It was solved also by replacing the ABV. I'm sure glad I didn't replace all the other parts that the codes indicated that were bad before checking the ABV. I hope this information helps others. I know I was going batty for a while.*
--
lhasaluvers
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On 28/03/2011 12:36 PM, lhasaluvers wrote:

similar issues with my '06 Ranger (3.0L V6) a couple years back and it turned out to be the same thing... sorry about that.
If it's not too late, don't throw the old one out, they can often be cleaned up and used again. BTW, the dim headlights when applying the brake was likely the engine revs dropping so low with the idle all screwed up that the alternator was no longer turning fast enough keep up (oh, and Ford actually call the "ABV" an "Idle Air Control Valve").
I hope that you appropriately rewarded your step son for saving the day!
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