My '95 Cadillac DeVille Concours with a Northstar engine occasionally stalls when driving. It happens only when the car is coasting with no pressure on the gas pedal an usually when it?s only been running for 5 or 10 minutes. I can go for several days with no problem and then it will recur. It always restarts just fine, usually while I?m still rolling if I put it in neutral and turn the key. There are no engine codes resulting from this most of the time. It can be a little disconcerting because, being a Cadillac, it?s designed not to show anything alarming and it quietly stalls and gives no indication at all until I notice that I have no power brakes or power steering!
I?ve taken it in several times to my local garage and later to the Cadillac dealer. The local garage replaced the 2 crank sensors based on some info on other forums. The Cadillac dealer was convinced they had fixed it with replacement of the EGR valve, but that didn?t resolve it. They said they talked to the Cadillac engineering department and could not suggest any other likely ideas short of just replacing thing until it went away. I replaced the air filter and the MAP sensor hoping to find it, but no joy. I had the idle actuator replaced about 5 years ago and thought this might be a bit out of adjustment, but the dealer says there is no adjustment. If this were an older car with a carburetor, I?d just adjust the idle a hair higher and be done with it.
Any ideas?
The problem might be with the Idle Air Control valve. I know you said it was replaced 5 years ago. But it’s not unusual for this part to start to malfunction after 5 years.
Tester