idle surge
 

I posted this issue awhile back, but still having an issue. wanted to provide an update to see if there are any new insights.

I replaced the O2 sensor and the fuel pressure regulator to no avail. engine harness is new. tried cleaning the air mass meter, didn't help. The onboard computer spit out several codes; 4, 6, 9 and 16, cleared those, then got a code 5 (egr). I have a new egr valve, haven't replaced it yet.

anyway, this is an intermittant issue, no rhyme or reason to it. cold, hot, long drive, short, whatever, doesn't matter.

If I turn the engine off and restart, it will usually run fine again, although inevitably, it occurs again. could happen quickly, or two days down the road.

thoughts? thanks!

...and this is ????????

right, sorry. 1995 E320 sedan

That will narrow it down...

Did you get codes from the other modules yet?

no, I had built a code reader, but left it on top of the car and it's gone. I'll have to build another sometime soon.

Well, you answered your own question.

Pin 8 and 14 would be of main concern for proper diagnosis......

If you want to take a stab in the dark at it...put a BB in the vac line to the EGR valve and drive the car a few days..see if it runs Ok [ disregard the EGR fault this will cause]....
That would indicate a sticking EGR valve common to that chassis..
there was a TSB on it.................................

My preference is code retrieval of all Engine Management modules , but that is only b/c I am lazy and want to get to the fault and a diagnosis fast.

Tsb?

TSB

Technical Service Bulletin