PeachParts Mercedes-Benz Forum - View Single Post - Rough Idle Update on 300TE....I'm totally out of ideas

pawoSD · #3 04-03-2009, 12:17 AM

Personally I'd probably try swapping a different fuel distributor on just for the heck of it....who knows, maybe yours has some weird internal issue that's causing it to not meter the fuel properly.

I've noticed that my M103 idles "rough" sometimes, and by rough I mean you can tell its idling, but its not misfiring (I've experienced that).....but at other times (most of the time) its so smooth you can't tell its running. Mine seems to get about 18.5-20mpg even with me being a leadfoot.....

I am being picky when I say it feels "rough".....my sister's van and my uncles cavalier engines both vibrate "in general" when idling.....by comparison the M103 runs like a fine watch....with a slight vibration sometimes.

Is the vibration strong? Or just enough to be annoying?

Have you considered trying...dun dun dun....Resistor spark plugs? I ran mine on the H9DCO plugs, and it ran like crap....well, it ran great for 50 miles, then it lost about 2 cylinders and ran horrible....got 11mpg and had no power. I quickly replaced them with NGK resistor plugs, and it has run beautifully since....and that was quite a while ago. When I took out the non-resistors....they were totally coked.

I noticed you've not replaced the fuel pump. Is it possible that it might be tired?