[Sheridan_]

I have a 2011 e90 335i with the n55 engine and when driving hard above 5-6k rpm my car with start misfiring and shuddering, I'll get a engine light and the car will get reduced power but it'll drive terribly even if I'm going slow. However if I turn the car off and back on it runs perfectly again unless of course I go above a certain rpm. Upon reading other forums I believe that is could be my hpfp but all the forums I looked at the codes were slightly different from my own and I also realize that it doesn't seem to be a common problem for the n55s. I have changed the coil pack for cylinder 4 just to see if that was the problem but no change.

These are the codes:

29D0 - Intake air temperature sensor, electrical: Short circuit to B+
2EE0 - Combustion misfiring, serveral cylinders: Fuel injection deactivation.
2EED - Combustion misfiring, cylinder 4: Fuel injection deactivation.
2EFE - Misfire, several cylinders: Damaging to catalytic converter or damaging exhaust gas.
2F02 - Misfire, cylinder 4: Damaging to catalytic converter or damaging exhaust gas.

Dme shadow (inactive) codes:
290A - Intake air temperature sensor: multiple fault.
2EF7 - DME: map thermostat, activation.

Also the 29D0 only came up today.
My car just hit 80,000 miles and has a catless downpipe and is tuned stage 1 with mhd.

[ghayes420]

Sheridan_

Did you find the fix for this by chance. We are having the exact same problem and have the exact same codes.

I have scoured the forums and read numerous postings.

Did you find the root cause of your problem by chance? Many Thanks in advance!

[whyzee125]

My previous N55 had a few injectors crap out with similar symptoms. I don't remember the codes but that sounds very likely to be an injector issue since plug/coil issues won't generally clear upon restart and they don't suffer the carbon buildup issues nearly like the N54's so so that's unlikely at 80k miles.

If you're a DIYer, swap a few injectors cylinder to cylinder and see if it follows.

Also be glad you aren't having to pay N54 injector prices right now lol