W168 P0303 Cylinder 3 Misfire Detected

[TheJoker]

Hi guys,

Recently my 2001 A-Class (W168) stopped running on all cylinders. I took the coil pack off and couldn't see anything seriously wrong, and the plugs looked quite OK.
I've borrowed an OBDII reader (Sealey VS8700 - nifty little thing!) and it showed 4 codes, which I reset, and then I ran the engine for a while and the engine light came back on. There were two codes, both the same number;
P0303 - Cylinder 3 Misfire Detected
My gut feeling (and hope) is that it's just the coil pack ? So before I go and order a new coil pack, I thought I'd run things past your immense knowledge.

The engine runs fine for a moment and then degrades. In fact, I thought it was fixed after I reset the codes as the engine was running smooth as silk. Then when I increase the revs it starts spluttering and doesn't want to rev past something like 4,000rpm. And after some 4 minutes of running the engine light, with the aforementioned codes, came on.

Any thoughts!?

Thanks!

 

[grober]

Is there a HT " cassette" on these? I have a feeling its a fairly common fault. My guess something is overheating causing an HT breakdown.

bert Rowe, Lofty's homepage. A-class info, Memo -SDcan EOBD/OBD" fault codes

and

Bert Rowe's-Mercedes-Benz 'A'-class info. Replacing Spark plugs, Special tools

 

[TheJoker]

Yes, the coil pack looks like this:

I've got Bert's tools to remove the cover, so I can pop it off and back on in pretty much no time.

I believe the coil packs are prone to break down, however, I just wanted to make sure there's nothing other obvious beforehand. Thanks!

Hmmm... which cylinder is #3?

 

[grober]

Courtesy of Bert.

 

[TheJoker]

Courtesy of Bert.

I've looked at that picture before! Thanks!

 

[TheJoker]

I just wanted to say that a £46 coil pack from Euro Car Parts solved the problem. Runs perfect now. Easy thing to fix with Bert Rowe's ignition pack cover removal tools and two Torx sockets.
Thanks guys!