95GT with Stumble/Hesitation problem. Need Help fast!

[FHP89LX]

The Car is all stock.This is what i changed:
First I ran Seafoam, then I changed the Oil. (The car was doing this before I ran Seafoam).
O2's sensors, wires, plugs (twice), Fuel filter, replaced MAF 3 times, Made sure MAF was cleaned. Put 93 octane gas from 3 different gas companys thinking that I might have a bad batch of gas, I did the injector cleaner stuff.

The car idles beautifull. When you drive part throttle it runs perfect. Then when I WOT, about 3500 to 4200RPM it stumbles or hesitates. Sometimes you can hear a faint poping sound. This happens when the car warms up. When the car is cold and you WOT it, it runs fine. On one or two rare ocasion it stumbled or hesitated but it does it the most when the car is running at normal temp.

This car is my Daily Driver and its really driving me nuts.

 

[sage2k]

mine was doing that and it was my cap and rotor, the cap and rotor even looked fine but replacing it fixed it, was cheap too

 

[KSelvig]

Similar Problem

I have just gotten my 95 GT running after almost 2 years garaged. I replaced all the normal tune-up items and starting driving. While the engine is cold, it runs great. After a warm-up however, it starts to hesitate and backfire above 2000 rpms. The idle is smooth both before and after the hesitation problem. The strangest thing is, if I turn the car off, even for 5 seconds and restart, it runs great again for a little while. Any ideas? I have been racking my brain to try and figure out what could be causing this.

Items replaced:
plugs
wires
distributor cap
rotor
water pump
thermostat
belt
cleaned K&N air filter

I am doing an oil change tonight as well as the fuel filter.

Please help!!!

 

[HISSIN50]

How is the coil? That's about the right cut-out circumstance for a weak coil (that's gotten hot and is taking a dump. When cold, it works ok).

If you have a bud with a coil you can borrow, it's worth trying.

That's also the sweet spot for a failing TFI.

Can you see FP when it cuts out? A FP on the outs (weak diaphram) can cause similar issues.



Good luck.

 

[FHP89LX]

problem fixed. Change out everything including the distributor. the car is my friend. He is one picky SOB.

thanks for your help

 

[BlownFiveLiter]

I have just gotten my 95 GT running after almost 2 years garaged. I replaced all the normal tune-up items and starting driving. While the engine is cold, it runs great. After a warm-up however, it starts to hesitate and backfire above 2000 rpms. The idle is smooth both before and after the hesitation problem. The strangest thing is, if I turn the car off, even for 5 seconds and restart, it runs great again for a little while. Any ideas? I have been racking my brain to try and figure out what could be causing this.

Items replaced:
plugs
wires
distributor cap
rotor
water pump
thermostat
belt
cleaned K&N air filter

I am doing an oil change tonight as well as the fuel filter.

Please help!!!

Well it seems the other person's problem is solved, but yours is still hanging out there. With the K&N, I'd suspect a dirty MAF. There's a fine line between perfect oiling of the filter and too much; too much being bad. Give your MAF a good cleaning, it probably has oil from the filter on the elements, which would certainly cause your problem. When you start the engine, your EEC disregards the MAF signal for a short period of time, so that's why you probably don't notice the hesitation.