QuestionEngine hard to start in cold weather and engine shuts off while driving. Brought van to two Chevrolet dealers to have fixed. Neither one could find what problem is. One mechanic changed small computer on engine that senses the air going through, but van still has problem. One mechanic thinks it is a vaccumn problem. Engine will quit while driving and "Service engine soon" light will flicker. Sometimes when this happens and I give it some gas, it will recover. Otherwise I lose all power. Generally car will restart if I shift to neutral and restart engine.
AnswerHello Roger,
They were both in the right ballpark, in my opinion. I just wonder why neither accessed the diagnostic codes.
By just your discription of the symptoms, it sounds like a vacuum leak, but the coming and going points to something that opens and closes.
One item on your car that does exactly that, is the EGR valve.
The EGR valve opens when directed by the ECM(computer), to allow exhaust gases into the intake stream.
There is supposed to be several conditions met for it to open, but when it opens, it is a direct vacuum leak.
I could get into the purpose, but you don't really care about that. It is an exhaust emission control feature.
Now, that valve is intended to be removed and cleaned, and not hard to do.
But for your problem, we just want to see if it is what is causing your problem.
The easiest way is to disconnect it, assuming that it is properly closed when off.
That will set a code, and turn the engine light on, but you can tell if it is causing the dieing.
But then...don't just buy a new one. It may be opening because it is told to, thus operating properly, and the problem could be in the sensors, or the ECM.
But it also could be that it operates normally, and just happens to close on a piece of carbon deposit occasionally, which holds it open, and creates a vacuum leak at the wrong time.
So I would have it removed, cleaned, temporarily bypassed, and see if thats it.
Good luck,
Van
