Good morning fellow techs.

25 yrs in the business, but before I do my diagnosis wanted to see if there were any tsb's or "common" issues for what I'm about to describe.

Vehicle cold or hot presents slight missing/choppiness that you can feel in your seat at 1500-2000rpm(in park). Under a load there is no miss at all and runs liked a raped ape, no hesitation or stumbling. Almost the characteristics of an faulty EGR in closed loop or even vacuum leak; however rpm is good and no surging. I as you could give a list of a hundred or more things that would cause this, "but wanted to know if there is or was a common problem with missing besides the obvious of plugs/wires and the list goes on. Although I see an "aftermarket" set of wires on this vehicle?

no codes, no light, no funny smells and the list goes on.

Thanks guys and perhaps I'll answer one for you sometime :)