Engine RPM Jump Before Shifting 1999 Grand Prix

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Question: Hi I have a 1999 Pontiac Grand Prix. I am starting to think that there is something wrong with the shift solenoid. The car is still in good mechanical condition, the check engine light never comes on, even though it still works.

I will be driving, at any speed, and when it comes time for the car to switch gears, sometimes its not even time, the rpm will jump up to 4000 or 5000 rpms and then finally change. It feels as though a teenager just learning to drive a stick is working the automatic trans.

Answer: This is an internal transmission problem on your car. This is not an electronic component problem inside. It is a mechanical problem inside the trans. A shift solenoid cannot cause the transmission to slip. That is what your problem is called- “Slipping”.

The RPM going so high before shifting means the it is sort of in neutral. Just as you described a kid driving. There still may be a code stored in the computer even thought the engine light never came on. This type of fault will not turn the warning light on, but will set a code. Probably something like P1800, component slipping.

You are going to have to have the trans data viewed with a scan tool by a mechanic while it is acting up to diagnose the problem.

But, most likely the trans is going to have to come out and either be repaired, rebuilt or replaced. Either way get ready for an expensive repair bill.


No Power Inside Car

Car has power under the hood but none inside or to lights.

Answer: You must have a bad fuse under the hood that power the inside fuse box, or possibly a burned fusible link. Be sure to check EVRY fuse under the hood.


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