Hello,

I'm currently experiencing a rough idle (in drive & reverse - not so much in neutral) on a 2000 w208 with approx 83,000 miles. Stealer-dealer told me they pulled a code for afaulty coil pack on #5 cyl. (they replaced the pack on #2 some 6 weeks ago), however, no repairs were performed as I preferred to find a good mechanic instead of using them. Note, NO check engine light EVERcame on for me, however, the dealer said they got one. I just took it in b/c it felt rough. I did get a CEL 6 weeks ago when the coil pack failed on #2, but that's all been fixed.

This was 2 weeks ago. Not sure if they cleared the codes, but I have yet to get a CEL. I just replaced spark plugs, andmechanic did a diagnostic. Hesays there is no fault code for the #5 coil pack, but that there is one for the transmission control module (ECU for transmission).

This is about where my knowledge stops. I've read a bit and apparently ECU resets can help rough idle. Please advise. I need to sort out the problem here. Will an ECU reset help? Do I need new ECU (unlikely, I hope...)?

Thanks

 

the spark plug wires on those benzs suck they go bad always on the 320s and 430s . might want to go there. coil packs are solid though rarely go bad.

 

Motor mounts are notorious for going bad on our cars. Could also be bad MAF.

 

Plugs and wires now changed. Situation is noticably better, but still not to where I am comfortable.

Just a thought lowphat - my mechanic says the car is throwing fault code for engine control unit. I'm hoping this is amisdiagnosis for a malfunction in MAF. I've never heard of this problem before but looks like it can mask itself as other failures.

We shall see.