Hello gurus,

I've spent quite a bit of time wrenching on older diesels, but I'm pretty new to the M104's.

I've searched the archives, and seen a lot of discussion about misfires on the M104 engined W124 E320's, but nothing that really seems to address my problem.

Car is a 1995 E320 with 155Kmiles. Car misses at idle when warm, and sometimes will hesitate on acceleration. Once things get above idle, or the hesitation stops, everything is good to go. Runs smooth at speed, and gas mileage seems to be OK.

Engine wiring harness is only about 25Kmiles/3 years old. All spark plug wires have been replaced. Plugs are the correct non-resistor BOSCH's, and I've double checked the gaps. I have built Arthur's code reader tool, and have pulled the codes several times. After replacing an obviously bad oxygen sensor, it looks like I'm left with only one recurring code. I'm still getting a code 11 on pin 14. Does this sound like the electronic throttle actuator wiring issue? Anyone know where in the FSM the holy gods of Mercedes have outlined R&R of said beast? I see lots of CIS stuff on the CD, but not much mention of the HFM system. Could it be a bad coil or two? Not sure how to test these short of throwing parts at it. I do have access to an oscilloscope, and could probably cobble up an inductive pickup, but I'm not sure if this would allow me to "see" the miss...

Any help would be greatly appreciated. Thanks.

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Gary Thompson
Georgetown, TX
1995 E320
1984 300D