Fuel trims 07 530xi
I was getting bank 1 too rich and bank 2 too rich codes. Car runs fine, no rough idle, no smoke and no noticeable loss of mpg and/or power. Maf sensor has been replaced in the last few years and the air filter is clean. I noticed originally my long term fuel trims were off the chart, -27 each give or take, at idle and in the teens at highway speeds. Short terms were always close to 0 or positive single digits. Today I was messing around trying to start diagnosing it and I noticed that the clip in pre filter (I'm guessing at the name) that says do not remove in the air box cover, was dirty as hell. Couldn't even feel compressed air going through it. I used some k&n filter cleaner on it and blew the **** out of it. Much improved air flow through it now.
Now my trims are different. Long terms are still high at idle but short terms are matching the numbers but on the positive side. 10-18. At 2200 rpms they basically even out. -15 long and +12-15. I'm due for inspection this month so I want to try to resolve this soon. Thanks