I've done several searches and found some possibly related info, but nothing on this engine that quite fits.

Our E420 (1994) bogs under hard acceleration (and more and more under moderate acceleration).

The check engine light is not coming on, we've replaced the wiring harness, MAF, plugs, wires, caps (etc) in the past 12-24 months. Check engine light came on for all the other issues, not for this at all. No recurring codes either.

It's been to two mechanics, the second of which has looked at it for a week and had the head mechanic from another Mercedes specialist look at it (that makes three shops). All are experienced with this model. One is a MB only shop, one does 75% MB's and one is a 'Euro' shop. Lots of MB's, Volvo's and BMW's.

He said there were some old codes from the MAF, but nothing recent and does not think that's it. They've checked the fuel pressure, vacuum hoses and fuel delivery hoses, everything in the air/fuel management system, changed in and out a few modules, etc. Nothing...

He's telling me he's stumped and perhaps have the dealer look at it. However, neither he nor I really think they'll know (How often do they service these vs. newer models?).

The one thing I saw searching were some 6 cyl W124's with dirty fuel distributors.

Any ideas at all?

__________________
Thanks,

Joey

'88 560SL Pearl Black/Java 152K
'94 E320 Anthracite/Grey 89K


Previously:
'94 E420 Black/Bamboo
'90 300E
'71 280SEL 4.5