[Kooner23]

Purchased and installed the Beck/Arnley Valve cover kit (gaskets and the VC itself).

Issues I'm having are:
1) When removing the oil filler cap, the valve cover sucks in air. I thought the N52 shouldn't suck in vacuum

2) Have a P0174 Code and P0171 code, lean bank 1 & 2.

3) RPMS were going up and dipping down, but once the car warmed up it didn't do that anymore.

[lowrydr310]

Originally Posted by Kooner23

Purchased and installed the Beck/Arnley Valve cover kit (gaskets and the VC itself).

Issues I'm having are:
1) When removing the oil filler cap, the valve cover sucks in air. I thought the N52 shouldn't suck in vacuum

Some vacuum is normal. There are a few posts (I'm too lazy to find them) describing how to properly measure it, but the fact that there's vacuum present whe you remove the oil filler cap isn't a bad thing on its own.

[QUOTE=Kooner23;25797314
2) Have a P0174 Code and P0171 code, lean bank 1 & 2.

3) RPMS were going up and dipping down, but once the car warmed up it didn't do that anymore.[/QUOTE]

This sounds like a leak in the intake or PCV system somewhere. Can you get a smoke test done?

[E90_Rage]

I recently went through something similar with mine after getting a new valve cover installed at an indy shop. I was experiencing a rough idle with rpm's bouncing around 400-800 with occasional stalling and the lovely smell of burning oil and "random" misfires at cylinders 3 and 4. Turned out to be a cracked crankcase breather hose and a leaking valvetronic motor gasket. Replaced both and the car is running like new again. Get a smoke test done, it will be the easiest way to find your problem.