So here it is so far, it started about 2 weeks ago, my wife's commuter. Started just taking off on her while at a stop light, then it would either come back down to idle or die, if it died it would be really hard to start, almost like you have to wait a couple mins. Then randomly it will start. But very slow starting, like "I think I can, I think I can" type starting. Almost like its flooded. Now when you start it, it basically wants to idle at around 1200-1400rpm, then will jump up to 3-4k rpm and hold there til it sees fit to go back to somewhere around idle. Very frustrating. Not sure what to check/replace next, but its getting expensive.

I have tested, IAC valve, Replaced TPS, Replaced MAF, tore apart TB and cleaned thoroughly. I have sprayed carb cleaner, 1 whole can over every inch of this motor, nothing. IAC valve reading (Resistance Testing) ALL-Data says it needed to be within 10.7 - 12.3 Ohms.....it was 12.3, dunno if that is good or bad. Have also tested the ignitor and both crankshaft position sensors as per All Data's specs also. Was withing range. Don't know if that rules them completely out, or maybe there is some other testing I can do to that area to completely rule it out.

Any help would be much appreciated.

-Freez

 

They were bad about getting carbon into the throttlebody butterfly rod bores. Once in there they eat at the rod/body. I have never had any success cleaning them once they get to that point. Anyway. Thats what it sounds like to me. It was more common on the earlier models however.

 

My 1993 929 3 liter V6 idled high between 1000 and 1800 RPM. I cleaned all the parts your supposed to clean.Same problem. Then turned the allan key screw on the Idle air valve all the way in. A little better. Then turn the throttle position sensor all the way to one side.A little better still. Down to 1100 RPM now. Then I found out about the Air adjustment screw. It's right on the throttle body. Turned it clockwise and the idle came down nicely to 600-700. i moved the Idle air valve screw back and put the TPS back to original position and re-adjusted the air and it's still idling at 700. It's right above the throttle arm on top of the throttle body. It looks like you bolt something to it but inside you see a screw.