95 escort - chugging on take off, bucking around 40mph

[daytrader]

OK, been researching the web trying to figure out what the heck is going on with my escort... Last week it started chugging while taking off. If you took off slow, it wasn't bad, but when you hit the gas, it was chugging, then it would take off.. Also, when you get up some speed, around 40mph, it would buck a few times. Did not do it all the time, but its more so now than last week.. First let me say that I have a fairly new timing belt.. Since the problem started I have put in a new fuel filter and air filter. There are a few sensore connected to the air filter area the will caus ethe car to stall if disconnected. I'm thinking its somthing like that. Here is some stuff I copied while poking around. Any help would be great!!

Thanks!!!

dirty idle control valve
try m.a.f.sensor first.disconnect and see how it runs,(might set engine code).check the cat and see if its loose,could be plugging exhaust on revs
O2 sensor
Unpluging the MAF will prove that the fail safe defult mode works and thats about it, MAF can go bad and cause bucking and drivability problems, but if it was tested I would move on to other things...like the O2 sensor.

also have a ’95 Escort of my own that my son was using while the mechanics were working on his. I got his Escort back from mechanic #1, who really didn’t have a lot of time to work on it for very long. My son came home this weekend and we started swapping and checking parts. We checked the following:

1. Timing belt WAS checked out previously by mechanic #2.
2. Had the catalytic converter and exhaust checked at Midas for back pressure, etc., and they said all is fine.
3. Hook up vacuum gauge. 15-16” vacuum at idle (same as my good-running Escort). We are at nearly 5000 feet above sea level. Unhooked ALL vacuum line from central manifold (vacuum distributor) and plug lines. Vacuum stayed about the same and engine ran the same or worse (normal, I’d say, for having some items not connected)
4. Checked EGR with vacuum pump tester -seems to work fine. Kills motor right away when vacuum is applied, returns to normal when vacuum removed.
5. Swap out PCM (power train control module) – no change
6. Ran with MAP sensor disconnected – no change (mechanic #1 had checked it previously and said it was ok).
7. Pulled connection from ECT (engine coolant temperature) sensor and test drive. IMMEDIATELY HAD FULL POWER RESTORED, but only for about a minute or two of driving and then resorted to it’s old self. Hooked it back up and poor performance continued. Unhooked again and same FULL POWER for a few minutes.
8. Swap out ECT sensor – no change
9. Ran with O2 sensor disconnected – no change
10. Swap out O2 sensor – no change

Nearly back to square one, except that we can maybe rule out a few things.
By pulling the ECT connection, we feel that we gave it a rich mixture and caused the excellent running for a minute or two, but what is causing the lean mixture is still a mystery to me.
I would check the fuel pressure again, could be a faulty FPR, should be 32psi at idel and jump to 40psi at WOT.

Did you reset the computer after swaping to a new O2 sensor?

It might be worth to try new ECT sensor.
throttle position sensor or the air bypass valve sensor is bad. also escorts are bad about the EGR valve clogging up with carbon. this can be fixed simply by removing and cleaning.
theres a hose going into the throttle body,
might it be an EGR valve or oxygen sensor?
Just an update for anyone who may be curious. I took it in and had it diagnosed....it's the throttle position sensor that's causing the jerking apparently. But naturally, that's not the only thing that needs replacing. My timing belt is in need of some help and the spark plug wires are arcing. Total of about 550 plus tax is the damage and 2 days with no vehicle.

Just this week my 1998 escort (148,500 miles) started the same thing. I replaced the fuel pump and the throttle position sensor last night. This morning it happened again and I had to hitch a ride on to work. I'm now told by a friend who had the same problem it is probably one of the oxygen sensors as that was what was wrong with his. I'll replace both of them this afternoon and hope for the best. Your problem may have been solved with the throttle position sensor but it did help mine.
I had posted earlier about an idle problem with my '98 Escort and I got some great suggestions. But after cleaning the fuel injectors, replacing the air idle control and checking for a vaccuum leak I still had a high idle. It turns out the problem was with the PCV valve. So, is anyone else is running into idle problems, you may want to try pinching that off to see if it makes a difference. It's a cheap fix.

[daytrader]

Well, out of nowhere the car started to run normal yesterday. Drove it 12 miles to a friends with no problems.. Half ways back coming home it started up again... Unreal...Someone siad to check the OS valve...

[Markgase2000]

Does the high idle go away after warming the engine? Does it just die when your in motion out of no where or does it give you a bit of warning when its about to shut off? exmpl(I was driving and slowed down for a stop and got heavy vibrations and popping sounds from the engine and it just stops running) if you tell us a step by step whats goin on when it happens , might be able to help more. I am willing to listen and help if i can.

[knockout_jab]

This may seem like I'm pointing out the obvious but I had the exact same problem on my 99 ZX2. Hearing all of the bad reviews on the poor transmissions in these cars, I was sure the hesitation in mine meant it was about to go as well. I went ahead and changed the spark plugs and wires knowing that it needed to be done. I never thought this would fix my stutter but it did. My suggestion--upgrade your wires and plugs to professional series. This fixed my problems but even if this doesn't fix yours, you should be impressed with the horsepower results.

[juan2]

try this to check spark plug wires.
when its dark in the evening . get a test light and hold it close to the plug wire . move it from one end of the wire to the other end . sometimes you can see arcing between the test light and wire.
you can aslo spray some water with a spray bottle
and then try the test light. let me know if this helps

[lawton_kid]

All are excellent things to check..........and one more.....

Pull the timing belt cover and recheck the timing. And more importantly, while your down there, check the vibration dampener (harmonic balancer) for worn keyway and also check half-moon key in crankshaft for wear and check keyway in crankshaft for wear. Any wear that would cause a problem will be noticeable. Also check the bolt holding the dampener on for looseness (when removing). Use lock tight on this bolt and torque to specs when reinstalling.

Good luck.

[daytrader]

Now I notice the problem when the A/C is turned on now... I had a timing belt put on several months ago so I doubt its that. It does not do it all the time. Very starnge. I do notice a idle drop here and there. Have not took it to a mechanic yet cuz I'm 99% sure I'll get screwed.. I'm mechaniclly inclined, but this one has me baffled... No check engine lite ever went on..

[amac209]

i'd be checking the engine to body grounds. did you replace the right ect ? there should be 2 one gage one computer. sounds like you've swaped out everything else. check the intake gaskets for leaks. an injector cleaning might help. oh yeah get your alternator checked!!! when they have 1 or 2 diodes burn out they still charge and put out the right voltage but the ac spikes can cause some wierd things to happen with the sensor outputs. if non of this works get some good insurance and leave it unlocked with the keys in it!!! good luck

[mightymoose_22]

This seriously sounds like spark plugs... how old are they? They are inexpensive enough to replace... plugs and wires for less than $30. This is the best place to start before jumping into bigger things. Also, if your car is a 1.8, you might have a problem with your distributor.

[chicagoareastuff]

I had the same problem with a 93 escort gt. Turned ot to br the air intake hose had a crack in it and sucked in more air than it should have. I wraped it with duck tape (love that stuff) The car ran great after that. so i replaced the hose.
chuck