[robajob]

Hello!

I have a 2011 F10 with the N53 engine. Occassionally the engine misfires when accelerating. Sometimes it does it once or twice in a journey, sometimes it does it every time I accelerate on a journey. But it doesn't do it every day. I've been noticing this since about July.

I often get the following error code (every day, or maybe every other day):
143101 - Rough running in stratified charge mode

I sometimes get this code (Not sure - once a week maybe?):
118402 - Fuel-air mixture too rich

I rarely get this code (twice in the last 4/5 months):
P0172 - Systerm too rich, bank 1

I have no check engine lights, no faults on the iDrive, no reduction in fuel economy, no rough idle, in fact no symptoms other than the occassional misfiring.

I did have the rocker cover changed back in March due to a leaking PCV valve that was causing a vapour leak.

I have changed all the spark plugs nearly two months ago. I couldn't afford to replace all the ignition coils, but I bought one and tried it on each cylinder in turn and the issue didn't go away. I pulled the spark plugs approx. 1 week after I replaced them and cylinder 2 looked more charred than the other two in that bank so I assumed fuel injector. I pulled the spark plugs again yesterday and they all looked the same.

I've checked the resistance on the injectors and they're all around 210 Ohms which I understand is correct for the Piezo-injectors. I've tried various other troubleshooting steps recommended in the Haynes Manual (but not all).

One thing I did find odd was the DC supply to the MAF sensor was 3.28V instead of a minimum of 4.8 - 5V, yet the correspoinding pin the ECU was reading just over 9V.

I've pretty much handed in the towel on this and have called a local, independent specialist to come and have a look. But I was wondering if anyone on here had experienced something similar?

Cheers for reading through my dissertation