When sitting still my tach reads about 100 rpm. Sometimes a little higher. What is the idle supposed to be? It used to read a little over 1000 rpm.

 

Idle should be about 750 rpms.

MikeyB

 

What was the cause? I'm having similar issues

 

I had issues with the tach jumping around at idle between 400rpm-750rpm. My truck kept popping camshaft sensor signal codes everyday. I replaced the sensor and when I did I realized the TST wire harness that plugs into the cam sensor wasn't fully locked. The orange tab was not fully engaged in the connector. It took a while but I finally got it engaged and the rpms on the tach are dead set on 700 rpms all the time at idle.

 

Thanks! I did not get any codes, but I'll check the plug if I can find it.