ScoobyDoo82 Posted June 19, 2013 Report Share Posted June 19, 2013 Just so this is easier to find in the case somebody else is having this problem down the line, I'll post a topic here. 1991 Pontiac Grand Prix, 3.1 V6 I've been having a problem with my car lately. When I start it up it immediately runs rough, to the point of nearly stalling. At cruising speeds I feel a slight stumble but otherwise runs much smoother than idle. There are no stored/current codes. Also, once I unplug the EGR valve the car runs perfectly. I eventually diagnosed it to a sticking open EGR valve. However I don't believe it to be the EGR valve itself as I took it off and cleaned it and all the pintles seem to move freely. I also ohm checked all 3 solenoids (digital EGR) and they're all within spec. According to the factory service manual, the EGR is grounded through the ECM using 3 sensors to decide... the throttle position sensor, coolant temp sensor, and MAP sensor. I've already tried putting in a spare ECM, and MAP sensor and the problem persists. I'm kind of at a loss right now because I'm not sure what my next step is as I don't want to disable the EGR and drive it like that. My only other idea is some wiring has rubbed through and is just grounding out all 3 solenoids. Quote Link to comment Share on other sites More sharing options...
ScoobyDoo82 Posted June 19, 2013 Author Report Share Posted June 19, 2013 (edited) Just threw on a spare EGR valve for shits and giggles. I got excited because it ran great for a few minutes... then did it again :| Only now it doesnt appear to be stuck open, unplugging it makes no difference. Edited June 19, 2013 by ScoobyDoo82 Quote Link to comment Share on other sites More sharing options...
Garrett Powered Posted June 19, 2013 Report Share Posted June 19, 2013 so its not the egr then? I wouldnt think so. is there a vid of it stumbling? or datalogs? Quote Link to comment Share on other sites More sharing options...
ScoobyDoo82 Posted June 19, 2013 Author Report Share Posted June 19, 2013 Well that did fix it. But apparently I have another problem with the wiring under the plenum. Quote Link to comment Share on other sites More sharing options...
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