What could cause hesitation at about 1500 RPMs

PRIORFAM

MEMBER
2000 PONTIAC GRAND AM
125,000 MILES

When car initially gave me trouble it was jumping at about 1500 rpms after it warmed up then progressively got worse and was doing this when cold also.I had unplugged map and tps sensors to see how it would react. Eventually brought it in to have it diagnosed and they said tps sensor code was indicated and would cause the symptoms. They replaced the tps sensor and said it was all set after test driving. However I picked it up and its doing the same thing after warming up. They said now theyre not sure but leaning towards pcm? I don't trust theyre evaluation. Its hesitating at 1500 to 2000 rpms and can't drive through it, its idling fine. Thank you

4 Replies

BRYBAKER

MEMBER
1 POST

Are there any other symptoms? I have never had a problem with the TPS or the map sensors. Is it throwing any other code? I had a problem with my 2001 Grand Am when the intake manifold gasket broke and began to leak. I had no knowledge that this had happened until my engine started working extremely hard to gain speed (3500 RPMs to get to 25mph). If you have lost coolant recently this may indicate a leak in the manifold gasket. When this leaks, coolant is burned in the exhaust and clogs your catalytic converter causing back-pressure into the engine, especially when the exhaust system is HOT. If you are car savvy check around your manifold and see if you can spot any leaks or signs of problems.

Good luck!