Lately my car stumbles when I accelerate from idle to about 2500 rpms. Its a weird hesitation, not like a misfire. The car idles good and steady. Recently I have installed Accel 22lb/hr injectors, new MAF, IAC w/minimum air set correctly, EGR valve, relocated MAT, SLP runners, TPS set at .54 volts, new ignition module, coil, plugs, wires, cap and rotor. My timing is set at 8*. New fuel filter and fuel pressure is at 48psi with vaccum line disconnected. Checked for vaccum leakes found a couple small ones and fixed them and there was no change. The car will also throw a code 32 once in a while when I first start the car in the morning but once the car has been warmed up and driven I never see the code again. Please help. Thanks.

 

One thing you might try is taking a look at that TPS again. I had a stumbling problem like you are describing a little while back. The min and max voltages on the tps were right, but when I hooked up a scan tool, I noticed that it did not go up smoothly. In the lower range just above idle it kind of jumped instead of increasing smoothly. Once it got passed that jump it was smooth. I replaced the TPS and everything was fine.

 

My car is doing the same thing. Idles fine, but at part throttle from just above Idle to about 2500-3000 it runs like crap. HUGE hesitations to the point that it almost seems like it stops completely for a fraction of a second. The higher the load on the engine the worse it is. i.e. most noticable in first gear.... least noticable in 5th(in same RPM range), probably due to the fact that it is already moving and not under as much load. I was thinking TPS too actually.

First I tried checking the timing.. it was right on at the factory setting of 6*.
Then I tried unplugging the battery for a while to reset the computer. After plugging it back in, this actually made it worse and barely drivable as mentioned above.

I'm going to try either replacing or testing the TPS tomorrow after work.

Hodge

I'll let you know if it works for me.

Good luck with yours.

 

Well, I was lazy and just replaced it instead of testing. Now the car barely starts and when it does it runs like crap. I tried the old sensor back on and it does the same thing. I'm going to actually test it this weekend and find the problem.

Hodge

 

well, I couldn't find my FP gauge so I borrowed one from a friend. tested my pressure and it was only 13 PSI. I replaced the fuel filter and it went up to 23PSI. I'm going to pull the regulator off tonight and check that out.

Hodge

89 formula.... did you ever figure yours out?

 

yeah I found a bad wire on my MAT sensor and I changed the EGR temp sensor and the car runs alot better and no more codes. I also have a custom chip on the way.

 

well my regulator looked fine. Guess I'm going for the fuel pump on Saturday