So I had an issue a few months ago where the car was misfiring. It's a 2004 BMW 545i 6MT with the N62. Checked DIS, it showed a misfire on cyl 7. Changed the coil & plug, no more problems.

Had another issue a few weeks ago. Checked DIS, it showed 4 cylinders misfiring. Cyl 1 (closest to me, passenger side) plug was CAKED with oil residue. Changed that plug/coil, car ran great.

Started to change the other plugs, and the car went back to misfiring and running at about 75% performance RIGHT after changing plugs/coils on cyl 5 & 6. Idle is choppy again.

I've since changed the coils/plugs on all of the cylinders except the very back two (the most impossible to reach). I don't think the problem is with those two, as they've never reported a misfire. At this point, these are the codes I get in DIS:

DME 2742 - Misfire detection cylinder 1 - misfire with cylinder cutout - Fault currently present
DME 2747 - Misfire detection cylinder 3 - misfire with cylinder cutout - Fault currently present
DME 2745 - Misfire detection cylinder 8 - misfire with cylinder cutout - Fault currently present
DME 275A - Ignition circuit, cylinder 2 - Ignition current increases too slowly - fault currently present
DME 2749 - Misfire detection cylinder 2 - misfire with cylinder cutout - Fault currently present

Another one that may not be an issue...

DME 2746 - Misfire detection cylinder 6 - Signal or value above threshold - Fault currently not present

This all started happening after we changed the plug & coil in cylinder 5 & 6. I'm fairly certain it has to do with cyl 6, as I can pull the electrical connector off the coil on #6 WHILE THE CAR IS RUNNING and there is no change in idle.

Another issue is that the car reports "High battery drain" and the car won't start if I let it sit for more than about a day (requires a jumpstart or push-start)

any ideas? This seems like it should be a simple problem to fix, but I have no idea where to go from here. If anyone knows of a good independent BMW mechanic in the San Francisco (Parkmerced / UCSF specifically) area, that'd be wonderful. I'd much rather take it into a decent shop that can diagnose the fault and resolve it correctly.

 

I know it's 3 years later but just wondering if you ever found out what was causing the misfiring?

 

If Cylinder 1 plug was CAKED with oil its a good bet that your valve cover gasket is leaking oil.

Step 1: Clean your engine so its spotless and replace the valve cover gaskets.