My car (see sig for details) has recently decided that it doesnt need to idle at the speed it has must to keep itself from stalling. I removed the IAC and cleaned it along with the throttle body and then I reset the IAC position did the min air setting and adjusted the TPS. It will now run decent but still has a really low idle in gear around 450-550 rpm but sometimes it will idle just fine around 650-750 so Im getting confused. I then tried to hook the tech 1 (GM OBD1 Scan tool) and it wont give me any codes or data, all it will tell me is that its waiting for data but it will sit there like that all day long if I let it. By this time Im getting rather irritated to say the least with the whole situation so I try the old fashioned read the codes with the ALDL jumped and it gives me the normal 12 code and then it flashed code 34 at me which I think I ay have set because it was idling so low when I was setting the IAC and TPS up. I guess if anyone has any ideas that might help Id highly appriciate it.

Thanks,
Travis

 

Anyone have any clues on this one? Im about to start replacing parts.

 

we are having the same problem with my bro's 87 iroc, it had a real choppy idle and the car wouldnt respond like before...already replaced the egr valve, IAC, TPS, wires, coil, plugs and swapped the MAF to see if anything changes, still have code 34 flashing maybe its the ECM?

 

Code 34 is a MAF fault (don't recall which one), but disconnect the MAF electrical connector on the underside of it, see if it clears up...if so, could be TPS setting/MAF relay/or MAF sensor.


AFter you've set the TPS to spec (.54v), checked it...then disconnected the MAF...report back on the findings and we can go from there

 

thanks i installed another MAF that was in working condition and nothing changed . i tried the TPS but i had trouble getting a reading from the TPS, i wasn't sure how to check the voltage from it? i wasnt aware of a MAF relay i'll look into that too

 

It may take some searching, but Trickster has posted the troubleshooting charts for code 34 on this board.

It's MAF gms/sec low error.

 

I have the benifit of using an actual GM service manual since I work at a dealership so the trouble charts are not a problem for me. My main problem is why cant I communicate with the ECM but I can still pull codes out of it plus I have this idle problem thats intermittant but it wont set any codes since I cleared them all.