Erratic Idle and Star Diagnosis
My car (96c280) has an inconsistent erratic idle or engine speed where it will surge at a stop or as I brake to slow down. I suppose it may do it at higher speeds but it would be less noticeable. I say it is inconsistent because it happens seemingly when the engine is hot or has been restarted after the engine has warmed up already.
I noted the possible causes, MAS, spark plugs, EGR valve, EGR tube, O2 sensors, wiring harness. My question really is that I plan to take the car to the dealer to have it fixed but I'm wondering how the dealer will go about diagnosing the problem. I've read where the posts where the dealers and independents have changed "everything" before fixing the problem (or not). How does the Star Diagnosis system work and does it fine tune the diagnosis in this and other situations? Perhaps the professional mechanics (Stevebfl, Benzmac) have some insight on this?