MAF or vacuum leak
Good afternoon everyone. I have a 2005 525 with a little over 77,000 miles. Last night I started it, and when it idled down, it started shaking, and I could hear that all cylinders were not firing. The service engine soon light came on, so I took it down to AutoZone today to have them pull the codes. Here's what they gave me:
1) 0301 - cylinder 1 misfire. Probable causes: plugged or faulty fuel injector, vacuum leak, or engine mechanical condition.
2) 0171 - system too lean, bank 1. Probable causes: faulty MAF sensor, large vacuum leak, low fuel pressure, plugged injector or cylinder misfire.
3) 0174 - system too lean, bank 2. Probable causes: faulty MAF sensor, large vacuum leak, low fuel pressure, plugged injector or cylinder misfire.
So, from this info it would probably be either a vacuum leak or MAF since BOTH banks are running lean, right? Which would be the more likely culprit, MAF or vacuum leak? I've read more threads about bad MAF than vacumm leaks, but I don't want to drop a bunch of $ on a new MAF sensor if it's not broken.
If you are leaning towards vacuum leak, are there any usual suspects on 5 series I should focus on first? I saw on one thread that there is a little corrugated hose on the lower boot, under the air intake. Any other places I should look?