So I have an issue with my recently purchased 94GT. It ran good for a while but now when I start it in the mornings it runs like crap until its warm and even then not up to full peak. When i'm driving down the road and I hit the gas to about 50% throttle the car spits and sputters but after about 2 seconds it catches like I hit the NO2 button. I ran Seafoam through the gas tank and then through the intake. What could it be? I am going to replace the fuel filter this weekend and see if that fixes it but if it doesn't where else should I look?

 

Ok so that didn't fix it. What else should I look at? I JUST replaced the plugs, wires, dist cap, rotor, and coil pack. I would really love to get it fixed ASAP so I can get back and fourth to work (a 40 mile drive one way). One other piece, since I bought the car the Smog pump hasn't worked because the pulley broke and I haven't fixed it yet. Could this cause this much trouble??

 

does the car have cats? they could be bad, pull codes firts, there is a writeup online to tell you how to do it. without running a diagnostic, its like spitting into the wind, check tps voltage, clean the maf, check the air filter, o2 sensors, but pull codes first

 

No, I just put on an off-road H-Pipe so no cats. I will pull the codes and get back to ya. What do you use to clean the MAF?

 

full tune up: plugs (autolite 25's for a GT), wires (and not the store brand pieces if ****), Cap and rotor, PCV valve.

Set timing. preferably in the 10°-12° area. Dont listen to the poeple who tel you to crank your timing up as far as it goes until you ping, then back it off... thats just horse****. i proved with my own car that I made more power at 12° than I did at 15°.

run KOEO and KOER tests, and if it continues, and you done have any failures, or hard codes, unplug the maf and see if the car runs better. (do this LAST)

 

I had the EXACT same problem. It was the 02 sensors. And since you just put in a new H-Pipe you obviously messed with the 02's. When you run codes you should get codes 177 and 176(lean bank right and left) along with a possible fuel pump relay circuit fault. Trust me! Took me 2 long enduring months to figure this problem out!

 

So both of them went bad at the same time??

 

No, not necc. My guess is only one went bad. That's what happened with me; only one went bad. But since they were both under warranty, I figured I'd replace them both. But now might be a good time to replace them both. I am pretty sure that is your problem. If anything, take them both out and shake them around. One sure way one is bad is if you hear something inside rattling.

 

You sir are a life saver! It definately ended up being the O2 sensors. I replaced both and couldn't be happier with the driving/idling quality now. Again, many many thanks!

 

I had a similar problem, my car seemed like it hadbad gas in it, turned out it was the coil. spittin and sputtering and backfiring.