So I picked up a 2006 3.0 two months ago and spent that time doing much needed repairs to it. Previous owner had performance issues and after the dealer raped them for nearly 12k in repairs a year ago and were asking another 5k more this time, she put the car up forsale.

Being a BMW mechanic for the better part of 10 years, I went in and did the basics:

-New fuel filter (old one was black)
-Air Filter
- 6 new plugs and a coil pack
-Lower intake boot replaced
-CCV system was done by the dealer a few years back
-Water pump/t-stat/radiator/hoses

Truck ran great. Due to the mileage (116k) I was getting ready to do the fuel pump as well since the one in my girls 2003 325xi crapped out 3 weeks ago at relatively same mileage. I used to change them all the time in 2007-8 when they had a rash of them failing due to all the ethanol.

Over the last few days I've noticed that it would long crank, sputter for a half second and then run fine on cold start. Warm start no issues. Drives perfectly fine. Priming the fuel system twice (turning the key on twice before starting) alleviated that issue, which made me think the pump is getting weak and not priming adequately. Also made me question the brand new fuel filter I put in since such issues are usually the result of a bad fuel pressure regulator (Mann Brand)

No codes up until this morning. Went to cold start the truck, long cranked and stumbled, except wouldn't really hold an idle. A few more tries and it runs, but I can feel a miss and hitting the gas results in a stall.

Fired up PASoft, got P0172 and 175 codes (banks too rich), as well as MaF shorted to negative. Cool no biggie, unplug and see if it will run better right?

Did so and still no change. But I do notice after 10 starts it will idle a bit better, but still down on power and doesn't want to accelerate. No misfire codes or anything aside from disconnected maf code.

Hooked up my snap on fuel pressure gauge which ironically find out doesnt work anymore, as it reads zero and the car is still running hahah.

Am I battling two issues at once here? Bad maf and a slowly dying fuel pump? I've dug up so many dead end threads where the issue never gets solved, and I read that changing the maf doesn't always solve the problem.

My friend has a Maf on order for me tomorrow, worse case I send it back if it doesn't work...

*edit* I also just filled up yesterday afternoon with 92 from a new station by my shop that is only 4 months old at the most. It had previously 3/4 tank from whenever it was last filled 3-4 months ago before being parked and I ran that tank down to 20miles DTE before filling up. Put about 60-80 miles on it since (Got it inspected/ran errands/dinner for valentines day) and not one quirk.

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8/06 build E53 3.0i....