would a tank of bad gas cause ur fuel trims to go wack and ur a/f to go a little richer? lnf motor after filling tank, suddenly my trims are going lean and a/f is going from 14.7ish to around 14.2 normal driving. also was getting a lot of knock in mild throttle

 

My fuel trims always go crazy right after i fill up. Possibly because of the evap system purging. Is it still doing it after driving a while?

 

well I filled with 10 liters of 94 when I could and the trims settled down some. they went from +7 down to around +3 and if I'm cruising they slowly fall back to close to 0, when I'm in town they go back up when on throttle and a little in boost. the a/f around swinging from 13.9-14.5 is odd though. the knock isn't as horrible but still there.