I have a 95 Ford escort with 186k miles and recently it's started "jumping and missing" (Best way I can think of to describe it, similar to empty gas tank or bad spark plug wire) after about
30-35mph. Up until this speed, the car runs like great. After that, blah.
Something else I have noticed is that if I press the gas pedal just far enough to accellerate, it's fine, but if I press any farther than that, it starts acting nuts again. Any ideas or past experience with same/similar vehicles?
This has stumped many of my friends because I've heard everything from transmission slipping to a faulty distributer cap to just needing to change the fuel filter.
While the filter is off be sure to check the fuel pump for volume and pressure-- and check the pumped fuel for water & debris.
And after the fuel filter I'd start looking for little parts of ceramic coming out of the exhaust. [or try shaking the exhaust system if it has some play] How old is the catalytic converter?
There are probably about a million things it *could* be.
Psibur, Our 94 Escort stationwagon is doing the same thing. We had the engine swapped and it's been doing it since. I want to say the timing belt is off but I haven't had time to verify it. It's not a faulty distributor cap because it doesn't have a distributor cap. it'd distributorless. I guess the fuel filter wouldn't be a bad place to start.
We did have some problems with it running lean because the mechanics didn't clean the intake gasket surface well and there was a huge leak and the EGR pressure sensor was broken. I'm not sure if they are related.
First thing to check is that you are getting spark. Connect a timing light to a spark plug and open and close the throttle plate really quickly. If at any time (when the engine goes nuts) the timing light stops emitting light pulsations, then you know you have a spark-electrical problem. Providing you have good spark then it is time to check your fuel pressure. Get a fuel tester and look at the pressure and compare it to specs. If it is not within tolerances, replace the filter and retest. If same results, replace the fuel pump. Also, make sure it is not the transmission trying to shift into 4th gear. Take off the overdrive and drive the car again over 30 miles. If the symptoms dissapear, say goodbye to your current transmission.
Here is one thing it COULD be...but finding if it IS it is a bitch.....
I had an 82 AMC Spirit....it had an electronic distributor and a "computer" module under the hood as well...
At one point in the late 90's I did a major refurb on it.....new distributor, filters, spark plugs, computer module (the old one had just died) etc etc.....
After that once in a great while at very high speeds on the interstate it would miss just a bit every now and then...but it was rare and since I couldnt figure out the cause I just ignored it...
Then finally all of sudden one summer it got really bad anytime I went over about 65 on the interstate....so much so that I had problems with it overheating to boot whether it was missing or not.....I musta tried 3 dozen things to fix the problem....
Then finally one weekend I had the car in the yard running ALL day long as I fiddled with every damn thing under the hood with the engine running at many different speeds....
Then at one point I got to wiggling ALL the wiring ALL kinds of different ways....
And after many hours of doing THAT....I found IFFFFF I wiggled one wire that ran from the distributor to the computer JUSTTTTT right....the engine would start missing and/or the timing would change significantly.....
What was the problem and how did it affect the engine?
Well, the wire in question (like most wiring) was made of a bunch of finer strands.....when I cut open the suspect wire I found a fraction of them were broken.....not ALL of them....just a fraction....so if you tested the wire for continity/resistance the wire would test out fine....
So.... how did THAT cause a problem?
Well, with the wire wiggling just right....the broken ends of the wires inside the insulation formed little spark gaps that the voltage would jump across...well guess what that does? it creates a nice spectrum of high frequency radio waves....those waves traveled up the wires and gave the computer fits.....causing the missing and erratic timing and overheating....
So, when the car moved fast down the highway....the wind under the hood jiggled that wire JUST right to cause all those problems....
I replaced that ONE wire (which by the way looked and felt fine on the outside) and the problem when away....
Good luck if you happen to have the same problem ! :)
Many thanks to all that replied with their knowledge and suggestions. I'll definatly come back and post a follow up if/when I find out what the problem is.
Finally solved this delimma. I was humiliated and enlightened the moment that when I pulled my spark plugs, one was really dark at the spark end. I changed the wires also and for my test drive, all was good.
Quite odd how such a little thing can cause such a huge problem, but then again, after working on computers for nearly 20 years, I can relate. :^)
Many thanks to all who have taken the time to help and give suggestions/comments/advice.
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