Expert: Skip Bollinger - 7/5/2007

Question
190,000 miles on this vehicle eqipped with a 3.1 L V-6. Engine check light intermittently comes on, goes off in a sporadic manner. Scan says Number three EGR solenoid. EGR is new. I have cleaned the port canal to the EGR and the EGR itself. Six months ago I cleaned carbon from this area. But recently it does not seem to matter if I clean it or not. The check light comes on shortly after reinstalling EGR. I recently took an 1800 mile trip and had no problem with the check light coming on - I got 35 mpg on this trip. When I arrived home and began short distant trips, the light came on. It did this prior to the trip and after the trip. Is the EGR so sensitive that carbon buildup from daily driving sets it off? I have noticed the engine idle roughly in the morning until it warms up after two or three minutes.

Answer
Jerry,
  I'm a bit confused but that is easy to do. Firstly, I'm not qualified to answer this question so I took it work to ask a Qualified Technician. I'm a Parts Professional if you look at my profile. But in discussing it with her, we discovered 2 things...
  You are messing with the EGR valve but the code set says there is a problem with the EGR Solenoid. You didn't mention that you have looked at the solenoid. Have you looked at it??
  The computer is vague as to how to test it and you may be better served going to the Public Library and look in the Reference Section for repair on your GA. In the computer, it says that your sol. may be "normally open" supplying vacuum to the EGR valve at all times or "normally closed" supplying no vacuum to the EGR valve. It did say that "normally open", it should supply 10" HG to the valve. Do you have a vacuum gauge to check this?
  You might also check the vacuum lines going to the sol. and to the EGR itself. Your reference to it idling rough and, after a few minutes, it smoothes out could be a small crack in a vacuum line that, once it heats up, expands and closes.
  That is about the best I can do. Again, I'm a Parts Professional, NOT a tech. Sorry to take so long to respond but I wanted to bounce it off some of my customers who are supposed to be techs.
  Good luck and thank you for your question..
Skip