Thanks for answering. It does run better with it unplugged, but not "normally". Check engine light is on and off, intermittent. It will start but runs really rough, and will race and/or choke out.

Bought part used from wrecking yard; first one didn't solve the problem, replaced with another from wrecking yard; no luck with it either. Is there some adjustment that must be maid after installing the part? Could two parts likely be both nonfunctional? Is there another diag for the same symptoms l...