Oldsmobile Questions? Ask a Mechanic for Answers ASAP
Welcome, I'm Chris (aka Moose), my normal schedule online is around lunch and after dinner past midnight.
Are you saying the tachometer shows the engine has reved up to 8000 rpms?
Is this misfire felt at idle?
Any trouble codes stored?
I think your reading the tachometer incorrect. Normal idle is 750. Nascars run at full speed about 8000. I believe you mean, its dropping down to 400 rpms at idle when its misfiring. Low idle issues alone are related to a dirty air fuel sensor, dirty throttle body or faulty idle air control. Sometimes a misfire is as simple as the vehicle just needing a tuneup.
Thanks for letting me help you & for leaving me a ~5 STAR EXCELLENT~rating when ready. Rating results in the website paying me from the question fee you have already paid. Although I appreciate customers saying "Thank You" that alone does not result in me being compensated if you were pleased.
Okay I understand now.
A scan tool is needed to see if the PCM shows this high rpm reading. If it shows accurate but the tachometer in the instrument cluster does not then the instrument cluster is faulty for the tachometer reading incorrect.
Hello again Chris here,
I have nothing to do with the fees. Use the contact us link at the bottom of the page to discuss that with the website.