tpastorok

Not totally sure what category is the best for this but TBI seems to be the best since I think the problem has to do with the electronics. Car is a 91 Camaro RS 305 TBI

So here's basically what happens:
I start it up and it runs super rough, like bogged down, and surges and comes close to stalling (sometimes does). To keep it from stalling i usually have to keep my foot on the gas, but after a minute or so all of a sudden it runs normally and idles perfect. I think it has to do with being warmed up because after this, i can turn it off and start it again and its fine. I have to let it set for around 30-45 mins for it to happen again.

I was reading on another forum about needing to clean somewhere between the egr valve and the intake. I haven't done this yet but i was wondering if someone could give me more info on how to do that.

I also think its possible that it could be the coolant temp sensor. Next on my guesses would be the MAP and then the O2. I've also replaced the ESC Sensor which i think helped it run better and i have a new ECM (not a new PROM) on its way. Any info would be great, thanks!

Schurkey

Put a scan tool on that thing. Does it begin running correctly as soon as the engine goes into closed-loop operation?

A REAL scan tool will also show you codes, and give you access to the sensor data. Should be easy to find from that info.

RS-Chevy-SS

Check fuel pressure. Should be the first thing anytime it surges

tpastorok

As for codes: I don't have a scan tool and I'm having a hard time finding a cheap one (low on money right now). I heard there was another way to pull codes without a scan tool, do you know anything about this?

I guess it would be when it goes into closed loop because its only bad right when it starts up, would this be a sign for the O2 sensor?

Fuel Pressure: I was having a pretty similar problem a month or two ago and we did check fuel pressure and it was fine. It turned out to be the ESC Module. I guess i should still check it again though, i just have to get a hold of a guage

tpastorok

This is so confusing lol. I just went out to see if the problem is still consistent...its not. I haven't started it since last night, I started it up and it ran fine while it was cold no foot on the gas. Once the idle finally dropped to normal operating temp it started to get really bad, i recorded it once it got bad so i can post a video, i read that to see if its a lean or rich condition you can pull the plug on the coolant temp sensor to trick the computer and see if it gets better or worse. It didn't change whatsoever. Would this indicate that it is rich? Or maybe the sensor is bad?

RS-Chevy-SS

Runs fine cold because the commander AFR is way rich to help keep it running. When warms up it leans it out pulling more air with no fuel pressure creates the issue.

What was the pressure last time you checked? It is possible for it to go back within that time though. Commonly is the rubber hose connecting the pump to the lines.

tpastorok

Okay sorry for all my confusion, I think I've pinpointed exactly when and what happens. If I start the car after its cooled down 100%, like overnight, it is good cold and then gets bad for a while. But then at some point it gets better. After that throughout the day if it cools off for like a half hour when I start it it is bad for a minute while I hold my foot on the pedal and then it gets better and runs perfect . I can't remember what the fuel pressure was because my neighbor checked for me, but he said it was what it should be.

Pushman

I'm having similar issues with my 92 RS 305. Did you ever figure out the problem?

camarowner

I have the same problem did you find out

camarowner

did you ever fix ? sounds like my problem

Pushman

My issue turned out to be the PCV valve

camarowner

Thanks for reply It was my fuel pump. runs great now.