erratic idle

[Carney]

My 7.3 rpm jumps from 500 to 800 while idling. I changed the fuel filter, took my superchips tune off and still doing it. I don't notice it while driving but it starts jumping after I start it or drive it for a few hours.

I have heard something about a wiring harness under the valve covers?

What would be the best code reader to buy and diagnose with?

Thanks!

[Strokeorcroak]

Take the oil cap off and smell for any sort of a burning smell. It will smell horrific and not much like oil. IF you have that bad smell that will lead you to the wiring harness under the valve cover to be burnt. Its semi common on these trucks and will cause what your talking about!!