E320 Idle Issue
 

I got my 320 Back on the road, Runs Beautifully, however at idle, there's what I'd call a Lope, The rpms drop, then recover etc I was told my fuel Tubes were filthy which I'll clean them out, but should I look at more? I was thinking about doing a tuneup now that it's working again etc. Open to suggestions

MAF

or....ETA

how would I go about checking them?

Or the rubber elbow (crank vent tube or other) that comes off of the bottom of the intake, ... crack and leak.

M104 engine has a non-OBD2 code system. You can make a code reader following some of the info on the forum here. MAF sensor usually goes around 130K or so and eventually throws a code, although you may get spurious other codes too.
Don't worry about your EGR tube, that just causes you to fail CA emissions, and doesn't give you bad idle.

well, if it makes any difference, the head was just off... and it idled fine before that..

How's the wiring harness? The insulation crumbles off on the W124 engine harness. Maybe you disturbed it.

I used MAF cleaner,and idle is fine.

Wiring harness is ok. but it's getting replaced as its about the age to do it, But I'm thinking it's the MAF or something.. I dont think it's a wiring issue

crc maf cleaner is only about 6 bucks at the auto shops

where's the MAF so I can check it?

I should describe this a little better, when I start the car, the car runs fine, then as it warms up, the RPMS drop to 3-500 then revive to 1,000 and stay there for awhile, then repeat the process. I'll grab a video of it etc soon

back to the top.

181K miles on the original wire harness must be some kinda record. I replaced the harness on my '95 E320 about 4 years ago when it had 64K miles on it. I had all sorts of idle and perforance problems that only got worse as I changed plugs, cleaned the MAF etc. I opened the old harnes and the wire insulation was a dry powder. I consider myself lucky that a short circuit didn't damage any electronics or start a fire.