craziest issues ive ever seen

[15913000gt]

today i started my car, and it backfired and ran absolutely terrible. i figured id let it run see if it would fix itself. and it did, when the car warms up it stops backfiring and idles good. anyone else had to fix this? if so what is it? what can it be? please any help would be usefull, i have no idea whats going on

[mb3000]

What year is the car.

[Turbo Beast]

Is there any maintenance record?

[15913000gt]

its a 91 vr4. i replaced the caps on the ecu if your going to ask that, and i have 115k timing belt oil and water pump just done, wich is when this started, timing is good checked it a million times, the only upgrade is a 3 inch downpipe. but thats it

[mb3000]

http://www.stealth316.com/2-fuelpumprelaybypass.htm

[15913000gt]

ill check it tommarrow, but would this make me run rich? also thanks alot for the reply i would have never thought that that could be it

[mb3000]

The extra voltage from this mod is minimal at best. For more voltage you're going to need a hotwire, but that's beside the issue.

[jstarr427]

Try pressure testing the intake when it's cold. I've seen cars run like shit because of vacuum leaks, when stuff warms up it expands, sealing said leaks.

[mb3000]

Originally Posted by jstarr427

Try pressure testing the intake when it's cold. I've seen cars run like shit because of vacuum leaks, when stuff warms up it expands, sealing said leaks.

Great post. I've experianced the same thing myself.

[15913000gt]

i pressure tested it after i blew an intercooler pipe off on the highway. everything is good, it held pressure and when i tooke the blow gun off it all the air shot right back at me. i am at a total loss, maybe from lack of knowledge of the car. but it seems to me like im overlooking something small but its obviously important. ohh and i tested the vacum lines on the throttle body for leaks too. theyre fine.