94 oldsmobile

I have a check engine light that activates when the engine is running about 2000 rpm and traveling on interstate. the engine feels like it stumbles or breifly stalls and tachometer drops from about 2000 rpm to 900 and back up quite quickly? could this be a faulty cam sensor? seems to act up after engine has reached operating temp. about 210 F. I have replaced the timing chain and crankshaft sensor etc. about 20,000 miles ago and engine has 186000 miles on it now.

Have the trouble codes read at a parts store and see what they indicate.

Don’t guess, find out.

Have you checked your ignition moduial, when you changed your timing chain do you inspect the cam shaft sensor for visibal defects. Cam sensor could be defective. The Advance auto here can test them.

Thanks for the reply; I was not aware that parts stores (whick ones?)connect an engine analyzer to customers vehicles to get the trouble codes. Do they charge a fee?

Most don’t charge a fee, but you may want to call to see if they can do a '94 Olds, this has the older computer system and plug.

Thanks again for the help and advice.