'94 K1500 Suburban 350/4L60E 120,000 miles
I notice a "quiver" at idle that has been going on for several months and is getting more frequent and more noticable. At idle (stop sign or in the garage, etc.) the engine idle lowers for a split second and then bumps back to normal, then bumps down and then back up to normal. Off idle, there is no problem and it runs great with no hesitation.
Everything is stock. Could this be the IAC? No codes show up. What are the suggestions at this point?