RPM Gauge Reading Low at Idle..

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Aug 11, 2013 | 12:40 PM

TheDude30425

Thread Starter

Junior Member

Joined: Jun 2012

Posts: 92

Likes: 1

From: Pittsburgh

Year: 1989

Model: Comanche

Engine: 4.0L

RPM Gauge Reading Low at Idle..

Hi there!

My Jeep for as long as I've had it has been reading my rpm's at around 200 rpm at idle.. I know this can't be correct, She runs fine, and It's only stalled out once in the past year. The gauge picks up when I give it gas just like it should, not drastic or quick "spikes" in reading just a steady with the throttle.

So, I'm wondering what the heck could cause this? TPS sensor? Crank sensor?

Any help would be much appreciated!

Aug 11, 2013 | 01:03 PM

Bustedback

CF Veteran

Joined: Feb 2010

Posts: 12,367

Likes: 23

From: Oroville, CA

Year: 1995

Model: Grand Cherokee

Engine: 4.0 with all of the noise and clatter

A bad tachometer is the most likely cause. But it could be a crank sensor, or even the cam sensor. You need to hook a scan tool up and confirm what the actual RPMs are. Sometimes you can pull the needle off of the tach and reposition it to the correct reading. I can tell you it's not the TPS.

Last edited by Bustedback; Aug 11, 2013 at 01:07 PM.