Questionhi ted. my 91 is a 4 cyl. 5-speed. this problem seems to happen more when the engine is warmed/hot, but no overheating. I'm in second gear and slowing down but not slow enough to drop into first, around 20 miles an hour. the car will then begin acting like it has an electrial shortage thats causing it to buck or lurch. the reason i compare it to an electrical short is that happened one time due to the ground being loose. with acceleration the problem is over. have been told its the egr valve. what do u think? also can u tell me some signs to indicate a blown head gasket? thank you, Gary. 150,000 miles on the engine.
AnswerIf there was an engine misfire caused by worn spark plugs or wires etc. the problem would be there all the time, especially on acceleration, but this is not the case.
A stuck open EGR valve is rare and would only cause a problem at idle, I don't see how it could cause this.
When this happens is the throttle completely closed and the car is decelerating or is the throttle open a small amount?
Usually if there is a head gasket leakage into the combustion chamber the oil will be contaminated with the coolant and turn it into a milky looking compound, remove the oil filler cap, if there is any evidence of the milky stuff there is a good chance that the head gasket is leaking, but again, I don't think it is causing the problem you are having even if the gasket was leaking.
