Hey y'all,
about a month ago I was driving my car and starting going up a small hill and it dropped rpm from 3000 to 1000 and wouldn't rev any higher and had loss of power. I pulled over and turned it off and tried to turn it back on and nothing. My buddy tried to help me get it started with starting fluid but nothing. Ran the codes and it said cylinder 6 misfire and that it was running lean, probably from the starting fluid. Got it towed to where I live and have so far changed the battery because it was in the 10v range, changed the fuel pump since it stopped priming, tried starting it without the MAF plugged in. The most I've gotten was a small sputter like it wants to start but it wont kick over. Any tips? 2006 530xi 155k miles

 

You need to read the codes with a proper BMW diagnostic tool. Until then, measure the voltage of the battery. Have you tried jumping it? Check all your ground cables, check fuses (seem obvious but do it if you haven't). Measure voltage going to starter, see if you have a starter problem. Loss of power, though not conventional is typical for BMWs with failing batteries. If you do manage to get it started measure the voltage to make sure the alternator wasn't the problem. The fact that your battery was at 10v could mean your alternator wasn't working. However, the car should still turn and start with a fully charged battery if the issue is alternator. Also, I am not sure why you would need starter fluid, don't do that again.

 

Sounds like the starter.

I have about the same miles on mine and I just had a no crank no start issue but when I changed the starter, she started beautifully.
Check to see if the solenoid is getting voltage from the battery...if so its a huge probability its the starter.

 

I concur! OP, grab a long stick, tap it on the starter and see if you get get the car started. Good luck!

 

Doesn't sound like the starter when OP says "The most I've gotten was a small sputter like it wants to start but it wont kick over."

Need to know all the codes.

ProTip: tapping the starter is old school and may help if the issue is a dodgy solenoid. Newer starters have permanent magnet motors though, and tapping/hammering on the starter body can fracture the ferrite magnet which will destroy the starter.