Idle problems on a 104 300CE ?'s
 

My car at first idled funky, not low, (well sometimes a while ago) but with the A/C on it was real rough, the hood bounced. Yesterday with the A/C off it went to like 250 rpms then rev, and down, etc, and died. Then i turned the A/C on, it was perfect, no glitch whatsoever, no roughness at all. I'm thinkning its definitely the clutch on the compressor, or the tensioner or something like that. I just wanted some input before I go changing stuff that might not fix it.

Do a search on "idle surging" this has been discussed many times with multiple solutions. I am also trying to figure out my surging problems with no success. This is a very common problem on the M104 and M013 engines.

Good luck.