Since it got cold outside my car started bucking under mid-hard acceleration. Feels like it looses power and comes back right away. From what i read here on the forums i tried disconecting the MAF to see if it would run better. Here is the weird part. Once i disconneted the MAF and drove the car the trans started BANGING!! into the gears. It became no longer an acceleration problem, it even banged into 1st gear when coming to a stop. Reconnected the MAF and now runs like it did before i disconnected the MAF. Any thoughts? At first i thought it was a motor related issue but after the Banging of the gears i start to wonder if its a trans issue. 528i with 150,000 pampered miles, auto trans. The car has had recent parts replaced including the MAF which i would be shocked if it was bad already, Cam and crank position sensors, plugs, air filter, fuel filter.

Been reading other posts and it may be a sticking MAF. It is new but i am running a K&N oiled filter so the MAF may be contaminated. What can i clean the MAF with. Carb cleaner?? i just dont want to spray it with something that will ruin it.

The MAF could be contaminated, oiled air filters will cause that, but it has no moving parts so it can't be sticking. CRC makes a special cleaner for the thin film aneometers is an MAF. You should be able to find it at an auto parts house

Turns out that it was a fuel pressure issue. Replaced the fuel pump and now runs like new. The trans also shifts very smooth now. Also cleaned the MAF with the CRC cleaner and put in a stock paper filter just as a precaution for any future issues.