OK, so last week I procured a 2006 X3 and about 100 mi into the 250 mi drive home... it lit the SES light. Mileage was great; about 26 on the highway, running smooth and no apparent issues, so I figured it was a camshaft position sensor.
Ran it by autozone and find the codes are P0171 & P0174 indicating lean condition on bank 1&2.
So, I picked up an intake boot and put it on a couple of days ago. The old one had some cracks on the smaller offshoot tube ( I guess that's for the idle speed controller?). No gaping holes, but it definitely needed to be replaced.
I've driven it about 100 mi since then and the CEL light is still on. So the $30 solution didn't fix the problem.
In the course of changing the boot, I had to remove the DISA and all looked well with it; it's intact and the diaphragm doesn't seem to be ruptured.
The car has about 100k miles; runs and idles great, so I'm pretty sure there is no major vac leak.
What's the next thing I should look at? I'd suspect the o2 sensors and, but it seems unlikely to me that they would both fail at the same time.
Is there any way to check the MAF? I thought about swapping it with my 330, but the MAF is different...