Multiple Misfires with fuel shut-off Cyl's 3 & 7

[65fastback]

So yesterday I'm driving and coming up to a red light as I'm slowing down the light turns green, I hit gas without downshifting and lug the engine a little, the car starts to jerk and miss and the SES light comes on, it continues to miss and I limp it back home a couple miles.

I check the codes and here's what I got:

ses 3.jpgses 2.jpgses 1.jpg

I have tried disconnecting the MAF, the car runs exactly the same. Spark plugs, pre-cat o2's done 15k miles ago, also I'm not buying that it's a coil, what are the odds of 2 going at the same time. Weird that it's on both banks of the engine. Fuel pressure at the rail is 48 psi at idle.

Any helpful questions or comments appreciated.

Thanks guys!

[edjack]

What did you get? Miles on the car?

[65fastback]

Sorry posted it on accident before I was done. Mileage 158k.

[bmac1996acc]

Mine did that. Cleared Codes and learn. Started the car. It shut off a couple times. Started again. It idled rough but stayed on and then smoothed out. I checked the rough without driving and it was high on 3 and 7. Drove for a short distance to set a CEL. Pulled the code and got cylinder 3 misfire. Swapped coil 3 with 4 I believe. Cleared codes and learn. Drove again just enough for blinking CEL (quarter mile with WOT). Cylinder 4 misfire. Rough was on 4 and 8. Ordered a whole set of coils since mine were all original (although some say to only replace as needed). I kept driving the car waiting on the parts after a couple of days it got really bad. Got home and checked INPA and had multiple cylinders misfire and rough. Cleared everything again. Drive ok for another day. On my way home from work stopped at store. Left car running. Start going down road flooring it and car barely moving. Got a couple of backfires. Switched car off while moving to reset cylinders that were disabled. Drove another mile or so and had to turn off car again and start while driving (6mt). I replaced all of the coils. Replaced all of the plugs. Did the VCG just because it needed it.

Car runs good now. I'm guessing coils or plugs or both. Could be a loose plug as others have had happen on here which could cause the same problem.

- - - Updated - - -

Another way to test coils is to disconnect the connector from the coils one at a time and listen for a change in idle. Only one of mine didn't affect the idle

[65fastback]

I guess I'll try swapping the coils and check the plugs too. It seems weird to me to get a misfire on 2 different banks at the same time and have it be coils, just to much of a coincidence.

[bmac1996acc]

I was worried about clogged cats from what I've read on here so I had my fingers crossed yesterday when I got everything put back together. I hope I didn't damage them from the time I drove with the misfires.

[rf900rkw]

Sometimes a bad misfire will trick the DME into blaming following cylinders too. 3 and 7 are next to each other in the firing order. As suggested, move a coil; and see what happens. If nothing, move the other coil.

[65fastback]

So I swapped cylinder 7 coil with cylinder 5 and the misfire moved to cylinder 5 then a couple minutes later I've got cylinder 2 misfire on bank 1 instead of cylinder 3. So I guess I just replace my cylinder 5 coil and go from there?

Also, thanks for the help guys, I'll report back.

[BMWpartstrader]

It probably wouldn't be a bad idea to have two new coils. Swap the one you currently have in 5, WO changing the plug or the coil boot(to attempt to isolate the problem). If that fixes your problem, you're good to go. If you still have misfire on 2, swap that coil as well.

[65fastback]

Just to update, I replaced cylinder 7 coil and it fixed all my problems. I learned something new, didn't know that 1 bad coil could show up as 2 cylinders misfiring.