M54 is M54 right?

[Factory6speed]

hopefully some more data for you ...

I am still getting the fuel trim / lean codes as well. I don't think there are any more vac leaks. The two caps on back of intake manifold were badly cracked. Also the disa was leaking. Idle has been fine. I did the valve cover gasket, but spark plug number 5 was still getting soaked. So I replaced the entire valve cover with new genuine and new gasket and that's nice and dry. The covers do warp apparently.

Since fixing those caps it's been a lot stronger but the trim / lean bank 1 and 2 codes shows up here and there. There has always been this small hesitation in 4th gear (manual) up a hill. This got worse for a bit after I last cleaned the MAF.

There was a post here somewhere saying that it's caused by the amount of ethanol in the fuel now. Around 2010 they added the 10% ethanol to the fuel and the DME software is still from 2005, for less ethanol. I did find a station here with 0% ethanol and have been trying that. It seemed better at first but I think just placebo. I may phone the good dealer about a software update. But there was also someone here that was using inpa to actually flash the DME tables, I would like to do that. I'm not aware of anyone making a flex fuel kit.

I'm doing the Vanos rebuild now to see if that helps with that hesitation. But then it's on to logging fuel etc, it might be a fuel supply issue. Or maf. I see a lot of posts about little o rings in the fuel supply system. I wish injectors weren't so expensive.

I also had the intake duct pop off of the maf connector once in traffic and the car barely ran, the EML light was on. Resecured that and hopefully that doesn't come off like that.

It shouldn't be this hard but it seems we all kind of fight these issues...