Is it losing coolant and, if so, the coolant isn't leaking under the vehicle?
If so, you're 88 has probably got a defective upper intake manifold that needs to be replaced. It is made of plastic on the 3800 Series II engine.
The problem will only get worse until it water locks (when the coolant is pulled into the cylinders preventing the pistions from moving).
You can get many local autoparts stores to read the ECU error codes which should give some indication of the failing part as well. Unfortunately, the error codes don't help much with the defective upper intake manifold.
Tuesday, March 16th, 2010 AT 2:40 PM