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I've been rebuilding my 89 Iroc 388ci w/ a super ram tpi.( car hasn't ran in 16 years) Engine is completely rebuilt and most sensors replaced. I started it up and it wasn't idling smoothly at all ,was running rich and tripped a 33 code. Which is a MAF code. I was pretty certain I need to replace that anyway before start up cause I didn't see any of the little wires in it. So after replacing the MAF I started it back up and it seems like it is running even richer then before and the idle is jumping around from say 800 to 2000 rpm. Just up and down then after a minute or so it will stall. If I unplug the MAF the jumping around at idle calms down a bit but it still runs rough and rich. Can anyone point me in a direction to go? I don't want to send it to a shop and waste the money. Any help will be appreciated?
Resurrecting this thread in hopes of some help with a similar issue!
I had my 1989 GTA 350 in storage for 17 years. After many new parts(complete fuel system, IAC valve, new TPS, entire cooling system, vacuum lines, full tune up, and lots of other things) the car runs.
The issue is a rough idle between 800-1000 RPM once warmed up and will just randomly die cold or warm. RPM jumps to around 2200 from a cold start and somewhat settles in that 900 RPM. When put in gear the car dies or idle drops dramatically to around 400-500RPM. If the car doesn't die when in gear RPM will jump high enough to push the car beyond the brakes and settle back down to around 600-700 RPM, then will randomly jump up and down to attempt to stay running. It idles extremely rough if it does idle in gear and again will randomly die, sometimes within seconds and other times it can run for several minutes. Seems to do somewhat better once it gets to operating temperature but still has an erratic idle, can die, or push beyond the brakes when the idle jumps in attempting to stay running.
There is no fuel in the vacuum line of the fuel regulator. The next things I have planned is to take the relays mentioned above(if I find them), MAF, then EGR valve and solenoid from my 1988 GTA with the 350 in it to see if any of that helps.
Also no CEL on.
Any help or thoughts on what to look at next is appreciated.
FWIW, I went through this a few years back and found a troubleshooting tree on this site that took me through all the steps. I ended up replacing the ECM. That tree saved me a ton of time and money throwing parts at it.
By tree are you meaning post #6 in this thread? https://www.thirdgen.org/forums/tech...ne-issues.html
BTW did you ever decide if you had a spare ECM if a guy needed one? I might be able to try the one from my 1988 GTA for the '89 having the issue perhaps, should be the same in both 350 cars.
Thank you again!
