Questions and Answers

Three Problems Q. 1992 Chevrolet Lumina Coupe, 3.1 liter, automatic transmission, 185,000 miles, fuel injection. Has P/S, A/C, and cruise control with rack and pinion. My car was in a repair shop for minor oil leaks, and when I got it home I had three new problems that started only after that repair job was done.

My A/C and heater are blowing from the defroster position only, and my cruise control stopped working also. The biggest problem is that my transmission is now shifting extremely hard. Any gear is a hard shift, but especially in the case of (example) slowing to a stop for a speed bump there is a definite jerk (seems like the whole car jerks) when the car shifts down right before the complete stop.

This jerk is especially noticeable when the car has just been started and moved from park to reverse, or drive. This may sound weird, but we took the car back because the car also acts like it wants to run faster than the transmission! As if its idled too high. The mechanic idled it down as far as he could, telling us the computer will just re-set the idle speed, and now there is a hesitation when taking off from a stop.

Since all three problems started at the same time, could this be a vacuum leak, or possibly the need to replace some sort of vacuum control? Unfortunately, I've had two mechanics tell me the machine they plug in to analyze the problem won't tell them the codes for the problem when they hook up to it, that it will only go so far and tell them no more. HELP!!!

G.M. in La.

A. It sure does sound like a vacuum problem. It is very likely that when they did the repairs a vacuum line was knocked off or connected up wrong. The higher than normal idle would tend to confirm this. I would go over each and every vacuum line and make sure they are connected, connected to the right place and that none of them are broken or cracked. Don't forget to check the PCV hoses as well.

Also check the electrical connectors. One may have been forgotten to be reconnected or is only partially connected. Unplug and plug them all back in to make sure they are seated properly.

Additional Information provided courtesy of ALLDATA