I have a 91 camaro RS, which had a 305 TBI and now replaced with a 350(over 30) TBI. For the most part, everything was going fine, everything was interchangable and is running. But the idle seems to be really jerky going from 5k rpm's to 10 rpm's back and forth, until i get it in drive and take it for a drive for about 2 minutes, then its not bad, its just fine for the most part. It does do it when on the freeway or driving at a constant speed sometimes i can feel it happening , as if it is still fluxuating as im driving, if i try to step on it, sometimes it hangs to kick in, it feels like the idle might have slid back down or hung for a second, then it kicks in and drives as normal.

Ive looked on the boards for people with similar problems, havent really found anyone who solved it though. i have checked for leaks, made sure the connections are ok, and advanced the timing a little because the car kept stalling otherwise. Also the car is overheating because the fan is not kicking on at the right time, maybe that plays a role in some sensor that could be causing both problems(for now i just turn on the AC for the fan to kick on, since AC doesent work anyway). The thermostat is new, the oxygen sensor is new, the engine is new, and the radiator is rebuilt, another water pump was put in, of course the spark plugs are new, the wires, distributor, rotor are new. the EGR valve was supposably replaced last year when i bought it.

At this time im ready for any suggestion, because im not really sure where to start, and what i should replace first, im running low on funds for this and i had the engine diagnosed at autozone for free, they came to a conclusion of an error 44, and the guy gave me a long sheet of paper for the problem, he dident really know what he was doing, but anyway, if anyone is the master of camaro mechanics, or has any suggestions, let me know, thnx.

 

"But the idle seems to be really jerky going from 5k rpm's to 10 rpm's back and forth, until i get it in drive and take it for a drive for about 2 minutes, then its not bad, its just fine for the most part."

Mine does that too, I think its just the stall convertor not locking up.

 

Carbine, I have a 91 RS and I did the same engine swap. Afterwards its idle would slip to about 500 then it would goose itself back up to 1000 and keep doing this over and over. I lived with it until I got a hotter cam and then the problem was so bad then that I bought a fastchip. That plus 350 TBI fuel injectors solved the problem.

 

It had better not be locking up at an idle.