Originally Posted by ahair121

So I just bought a 2003 X5 4.4i for super cheap (206,000 miles on it). Daughter inherited it from her father who passed away. She drove it to her house and it sat for close to a year. When she went to start it for the first time it ran rough and died. So I thought I'd give it a shot. From what I've been able to see he took care of it and had it serviced regularly. Before he passed he had all the cooling lines and the engine gaskets replaced.

First thing I did was pump all the old gas out of the tank and I put in 5 gallons from Chevron with two bottles of sea foam. I also replaced the fuel pump. I took out all the old spark plugs (which were wet with fuel) and put in new NKG plugs. I've tested both crankshaft position sensors with my multi meter. When I touched them to my wrench they didn't go all the way to 0, but I think it was .04 so probably fine right? I cleaned the throttle body (which already looked pretty clean) and the MAF. I also charged the battery.

When I start the car sometimes it'll start strong then quickly idle rough below 1,000 rpm, sometimes it'll backfire once from the intake while starting. If I pump the gas it won't really make it much higher than 2. If I unplug the MAF I can get the RPM's high and hold, but once I let off it dies right away. I replaced the MAF with a reconstructed Bosch from O'Reilly but the same thing happens. The OBD reading shows on both MAF's 10 g/s and it'll quickly dip to 6 for a second then back to 10. So I might have been lucky and gotten a bad MAF, but I'm hoping I can get some more direction from you guys on what other things I should try next.

I'm not a mechanic, but I'm mechanically inclined and I've done head gaskets, I brought a 2001 330i back to life by reading forums and watching YouTube. So I can follow instructions real well, but not experienced enough to diagnose. If you guys can just give me more ideas of whats wrong that will help me out a lot. In the mean time I'll keep searching through forums.

Codes I'm getting
P0343 Camshaft Position Sensor "A" Circuit High
P0363 Misfire Detected - Fueling Disabled.