The cars a 92 Z28 w/350 TPI, 700R4. Its got a MSD box, Headers, 3in Exhaust, Ported Plenum, and a Nitrous plate.

It seems like the car only stalls when its warm. It will stall going from Park, to Reverse, or from Park to Drive. It will also stall out when sitting at a light for a long time. I read that it should idle around 500 rpms in drive, but I think thats way to low. Every time it drops below 600 rpms its going to stall unless you give it some gas.

I checked the timing and it was at like 14 degrees. Do almost stock L98's like that much timing? I thought that was alittle to high knowing stock timing is 6 degrees, so I know have the timing set to 10 degrees at the moment.

Next I looked at the throttle body and the IAC passages where filthy, and you couldn't feel the IAC motor working. So I took the throttle body off and cleaned the passages as well as the IAC motor. Bolted it all back together and you can feel the IAC motor moving.

Then I hooked up my laptop to check the TPS voltage, and at closed throttle it read 0.53 volts. I didn't check TPS voltage at WOT, cause I figured at closed throttle it was dead on.

Now it seemed like all the common things that could be causing the stalling was where it should be, but the thing is still stalling.


Any help or ideas would be greatly appreciated.

 

Engine stalling can be caused by several things. In my experience, these are the most common...

1) vacuum leak
2) clogged fuel filter
3) fuel pressure instability (failing pump)
4) control module in the distributor failing

I would check these (in the order above) and see if they all checkout ok.

Hope this helps!

 

i had the same problem ended up not having enough backpressure so it stalled out when i changed gears i got a new exhaust system and it fixed the problem and the car ran better all around