I'm having difficultly determining where the problem is in my 1998 Jeep Grand Cherokee.
Symptoms:
Engine RPM drops randomly while driving (typically this happens when I let off the gas or when the cruise control lets off the gas, the RPMs will suddenly drop dramatically, then bounce back up after usually one to three seconds)
Dash lights dim, sometimes almost out completely, then brighten up again.
Radio controls - when adjust the bass, treble, mid range the small yellow light on each control which is usually steady, goes out while I make an adjustment. After making the adjustment the light brightens back to normal. Rest of the dash lights appear unaffected.
I'm wondering if something is grounding out somewhere, or would the alternator cause this, or is the PCM module the more likely culprit?
Any thoughts would be appreciated.