Problem: A 1994 e320 with a looping idle on occasion. Loops from the 700 to the 1200 range a half dozen times before settling down (note, only in park or in neutral).

The check engine light came on and my mechanic (Enrique on Reseda) said it was the O2 sensor so I had it changed. The light came back on and the idle looping returned once in a while so, based on research on this forum, I changed the coolant temp sensor. No luck.

I took off the MAS and cleaned it with MAS cleaner and it was better for a day but the check engine light came back on and now its looping a bit more often. Maybe I made it worse.


Can it be anything else but the MAS at this point with the intermittent looping idle. I figure if it was a vaccum leak it would be a constant looping idle?

The car has 120k miles and the harness was done at about 80k.

Thanks in advance for the help!

John