[Gr44]

Hi all,

I was hoping someone here might have some insight into an issue I have with my car at the moment, any help would be very welcome!

The car is a BMW E92 330i N53 engine. It has 71-72K on the clock. No modifications to the car to my knowledge, regular oil changes since I've owned it.

The issues started a couple of weeks back, I was driving in the evening around 7pm in 3rd or 4th gear going up hill if it makes any odds. At around 5K RPM, the engine seemed to hit a flat spot, by this I mean foot was to the floor or close enough but suddenly the car stopped pulling, the revs were steady. I geared up instinctively as it almost felt like it was on the rev limiter (no bouncing of revs though)

Anyway, this happened a few more times, always in 3rd or 4th gear, always seems to be around 5K rpm (give or take ~500rpm).

One evening the same thing happened and for better or worse rather than ease off or gear up I kept my foot planted, the engine warning light flashed a few times then came on solid, once pulled over the car was idling poorly (misfiring). After restarting the engine it was running fine again (to my knowledge!)

Next day I took it to my local guy who put in an OBD reader and it came up with the following codes in the ECU

A0B5 - Road Speed Signal Sensor
2AEC - Nitrogen Oxide Sensor Self Diag.
29D1 - Combus. Misfire Cyl 5
29D2 - Combus. Misfire Cyl 6
29D0 - Combus. Misfire Cyl 4
29CC - Combus. Misfire Several Cyl.

He wasn't sure what the underlying issue was, I've since spoken to a BMW dealer who were frankly useless. I've put some Slick 50 fuel treatment in as I was wondering if an injector was clogged, it's made no noticeable difference and the fault described above still occurs.

This issue is intermittent, I cannot constantly produce this fault but the criteria in which the fault occurs always seems to be as I've described above.

I've also since found out the N53 had a recall on injectors, at least 5 injectors were replaced under warranty according to BMW, I'm unsure on the 6th one (or which cyl that actually is)

I'm stuck at the moment as I use the car for track days but if it's likely to be a large bill I'd sooner P/X it in than drop a tonne of money replacing random bits in the hope it'll resolve the issue, I'm hoping someone hear has some insight greater than mine? (I'm not very mechanically minded!)

Many thanks for reading!

Sean

[Phil325i]

As the fault seems to limited to cylinders 4, 5 and 6 I'd guess a failed sensor in the exhaust serving that bank.