RPM's jumping around

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Oct 27, 2011 | 08:58 AM

B Big

Thread Starter

Senior User

Joined: Feb 2009

Posts: 148

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From: Western NC

RPM's jumping around

I have a '95 4 door dually. Driving down the road I just noticed a slight vibration and that the RPM's are jumping around a bit, like 100 or so.

Any ideas?

Thanks!

B

Oct 27, 2011 | 11:37 PM

oldbird1965

Fleet Owner

Joined: Aug 2004

Posts: 20,419

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From: AZ

I would say VSS or CPS, but I don't know for sure. Mine will do it when I'm running lite but not when I'm loaded.

Oct 28, 2011 | 08:25 AM

DIYMechanic

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Joined: Dec 2010

Posts: 10,121

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From: Orrville, Ohio

Is this with the cruise control on or off? If it is with it ON, I'd say VSS, if it with it OFF, I would try cleaning up the TPS in the Throttle pedal assembly. They can get dirty and read funny causing the PCM to "hunt" a bit for throttle application. Just take it out (two wire connectors and three nuts) and clean it out real good with a good quality electrical contact cleaner.