[TitanLH8]

I've been getting the dreaded Engine Malfunction warning every time I step hard on the accelerator. Using a scan, I'm getting a P0174 Bank 2 Too Lean error code but once I stop and start the car again, the code and error are gone.

I've been browsing the forum threads without any true resolution...ppl talk about cleaning the MAF but N54 doesn't have a MAF so the next logical thing that comes to mind is the fuel filter. Would that be the next thing to try to troubleshoot or are there other components to check first?

I have 115K on my 07 E90 335.

[arkie6]

What is the index number on your fuel injectors?

I had that same code off and on for over a year and then started getting the bank 1 too lean code as well.

I was also having a progressively worse warm restart rough idle issue.

Fuel rail pressure was normal at all times I checked as well as when the codes were occurring. I was using an OBDLink LX scan tool for checking codes and reviewing freeze frame data to see what the engine was doing at the times the codes were being thrown.

I concluded that it had to be leaking fuel injectors after shutdown that was causing my rough idle. The injectors were also likely partially clogged with degraded internal components and that was giving a poor fuel spray pattern and causing the the too lean engine codes.

I replaced my index -07 injectors with the latest index -12 injectors and my warm restart rough idle issue went away and I no longer get the bank 1 and bank 2 too lean engine codes.

Just something to consider. I have 105,000 miles on my '08 335i.

[TitanLH8]

Originally Posted by arkie6

What is the index number on your fuel injectors?

I had that same code off and on for over a year and then started getting the bank 1 too lean code as well.

I was also having a progressively worse warm restart rough idle issue.

Fuel rail pressure was normal at all times I checked as well as when the codes were occurring. I was using an OBDLink LX scan tool for checking codes and reviewing freeze frame data to see what the engine was doing at the times the codes were being thrown.

I concluded that it had to be leaking fuel injectors after shutdown that was causing my rough idle. The injectors were also likely partially clogged with degraded internal components and that was giving a poor fuel spray pattern and causing the the too lean engine codes.

I replaced my index -07 injectors with the latest index -12 injectors and my warm restart rough idle issue went away and I no longer get the bank 1 and bank 2 too lean engine codes.

Just something to consider. I have 105,000 miles on my '08 335i.

Originally Posted by arkie6

What is the index number on your fuel injectors?

I had that same code off and on for over a year and then started getting the bank 1 too lean code as well.

I was also having a progressively worse warm restart rough idle issue.

Fuel rail pressure was normal at all times I checked as well as when the codes were occurring. I was using an OBDLink LX scan tool for checking codes and reviewing freeze frame data to see what the engine was doing at the times the codes were being thrown.

I concluded that it had to be leaking fuel injectors after shutdown that was causing my rough idle. The injectors were also likely partially clogged with degraded internal components and that was giving a poor fuel spray pattern and causing the the too lean engine codes.

I replaced my index -07 injectors with the latest index -12 injectors and my warm restart rough idle issue went away and I no longer get the bank 1 and bank 2 too lean engine codes.

Just something to consider. I have 105,000 miles on my '08 335i.

Thanks for your input. How would I go about checking the index number of my injectors?

[arkie6]

Remove the plastic engine cover so that you can see the fuel injectors. On the side of the injector black housing facing the spark plugs will be a part number 1353 7585261-XX at the top of the injector where XX is the injector index number. 12 is the highest currently available. My old injectors part number ended in -07 (index 07). See photo in link below for an index -12 injector.

Note that 1353 7585261-XX is not the part number you use to order new injectors. The BMW part number for the N54 injectors is 13-53-8-648-937.

http://www.1addicts.com/forums/showp...2&postcount=13

This is the best pricing I've seen on these injectors:

https://www.ebay.com/itm/Genuine-Rp-...wAAOSw9KhaNU8q

[TitanLH8]

I'll try to check that out this week. Thanks for the advise!

[dsjr2006]

Definitely check the injectors. They're less than $130 from FCP Euro right now (https://www.fcpeuro.com/products/bmw...or-13537585261).