I receintly did a motor swap in my 91 RS. The TPI motor was running great and I was driving the car. However, a few days ago I went out to start the car, it cranked, fired, and stalled. If I give the car very little gas, it stays running, until i let off the throttle. When I'm giving it throttle, it runs smooth and sounds great. I assume its a VERY minor problem becasue the motor sounds great. Has anyone had or heard of this before? Any help would be great!!

The motor is a 1988 rebuilt 305 TPI put into a 1991 RS original V6 car with a 1991 Z28 Speed Density Wiring harness.

 

Make sure the IAC is functional.

Verify the TPS voltage. Even though the S/D systems should learn the TPS voltage at startup, there is still a maximum range.

 

Thanks, I'll be working on the car tomorrow night, i'll definatly check that. is there a posibility that it could be a gas problem? I know the sending unit on the fuel pump is busted becasue my gauge doesn't work, is it possible its not sending enough fuel on start up but when i give it throttle it can pull more? I'll be using a fuel pressure gauge as well tomorrow night, but just trying to trouble shoot so i know where to begin. Thanks!

 

same thing happened when i bought my car ..

i took off the throttle body and a couple cans of brake cleaner later .. and a new tps and iac .. and presto .. it purs like a tiger (not a cat ... there too *****) ... lol ... oh .. and a new fuel filter .. mine was clooooogged .. suprised it even ran ..

neways .. try that .. if not ive seen somewhere about a fuel pump relay .. idk ..

 

Okay, I just checked the fuel pressure, and its good. Its definatly an air problem at start up. I checked the IAC and cleaned it thinking that was the problem, but the cleaning didn't help. It might be busted, i have to test it. I also played with the TPS and it didn't seem to make any difference, the car purs like a tiger as soon as i give it throttle still, but when i let off, its dead in under a second.