I'll do my best to explain this.
Runs great at all RPM's except at idle. At idle it has an erratic skip. Sometimes it is barely noticeable and at other times it drops low enough to make the lights dim. I notice it more when it is warm. When cold it runs smooth.
There are no check engine lights on. It has about 145K on the clock. It also happens with AC on or off. If I two foot it and bring the idle up about 100-200 rpm it is still noticeable.
Any suggestions will be greatly appreciated.