Rough running at high power above 2000rpm

[MJK1]

My M5 runs quite rough above 2000 rpm at high power. It feels like the engine management is retarding the ignition and then it tries again and so it goes on. I’ve been using the Costco 99 RON fuel but I’ve now put in some Shell 97 and the problems still there. Anyone any idea what the problem could be?

[SapphireM5]

Fuel pump, coils plugs, maf etc. run your codes

[M5Rick]

I wouldn't use anything but Shell V-P and it's 99 ron.Cheaper supermarket fuels just haven't the additives and lubricants that SVP has; Try putting some injector cleaner in like red x and check when the fuel filter was last changed.

[MJK1]

Finally got the ISTA+ software and ENET cable to enable the fault codes to be read. The photo below shows the codes triggered by this misfire problem, anyone any idea which component will be at fault to cause these codes?

[MJK1]

Got the problem solved. I changed the plugs but no difference, full throttle misfire at 2000rpm was still there although it didn’t trigger any codes. I’ve just changed the coil packs and much to my relief, the misfire has completely gone. The car has done 60000 miles and coming up to 8 years old so not surprised they where starting to give problems.

[SapphireM5]

Originally Posted by MJK1

Got the problem solved. I changed the plugs but no difference, full throttle misfire at 2000rpm was still there although it didn’t trigger any codes. I’ve just changed the coil packs and much to my relief, the misfire has completely gone. The car has done 60000 miles and coming up to 8 years old so not surprised they where starting to give problems.

Glad you got her fixed and it was nothing serious. Thanks for updating the thread and posting the fix. Enjoy!

[technician117]

I would clear those old codes, drive for 30 minutes or so and then recheck the codes. You might have a MAF going bad as well.

[MJK1]

Originally Posted by technician117

I would clear those old codes, drive for 30 minutes or so and then recheck the codes. You might have a MAF going bad as well.

Thanks, I cleared the codes when I changed the plugs 2 weeks ago. The misfire was still there but no codes were triggered in those 2 weeks. I’ve now changed the coil packs, which has sorted the misfire and the codes remain clear. I will continue to monitor for any codes going forward and come back on here if any are triggered. I remain hopeful though that the problem is solved.