So i have a 92 RS that was a 305 v8 with TBI when i bought it, i recently changed it over to a 350 and used all the same stuff from the last engine. so now it is a 350 with the 305's TBI setup. anyway when i start it up and try to drive cold the car bucks really hard and stalls randomly or when i stop. when the engine is warmed up it drives fine and dandy until i hit a stop light or something then idles real rough and dies. ive also noticed my air filter is getting extremeley dirty now too. I also have a smell coming from the car but i can't tell if its exhaust or gas. it seems to idle fine while im in park but in drive or reverse it just dies out. i was thinking it may be the IAC or the EGR valve but im just not sure im the furthest thing from being mechanically inclined, took it to the mechanic shop on base ran by nappa they couldnt get any codes off of it either. the problem is getting worse daily i need some suggestions. for the record my fuel pump is new and i have no leaks from anywhere that i can tell. So what the hell is causing this and how can I get it fixed because its getting old and fast.

 

something is wrong with your fuel system.

 

oh ok that summed it up lol sorry for sounding like a dick anyone else give more specific on what the problem would be saying that was like saying "oh the guy who robbed the bank was tall and had dark hair"

 

Has this combo (350 with 305 electronics) ever ran good? If so, I would suspect a low fuel pressure may be worth checking.

If not, the PROM does use the engine size to meter fuel, which is important for a speed density TBI system, and it may be running lean.

If an EGR valve were stuck open, you would get stalling at idle. You can make sure the diaphragm moves freely on the valve to see if this is a possible issue.

The IAC is not likely a problem, but you could disconnect the plug and see if the engine behaves different.

 

sorry but like i said im not a mechanical person what is a PROM and i just did my 305 to 350 swap last month it started to just act this way with the idle before the swap i figured it was the 305 since i was replacing it anyway. i had ot replace it due to bad piston rings and a blown head gasket so a new motor was just about the same cost and the shop had a rebuilt 350 so i said sure. i bought the car in july and when i took it for its tune up it did come back saying i needed a new egr valve i think ECM

 

prom is your computer chip inside the car, under the dash, passenger side.