Quick background- 2011 Caprice tune was done with procharger but there is currently no head unit. The car sat all winter and I just had it out for the first time last weekend. I have not changed anything in the tune but I replaced the head unit with an air filter until I get a new one. I was doing some logging to be sure everything seemed ok. I noticed my fuel trims are significantly different from bank 1-2. i went back and checked some logs from last year and this also seemed to be the case. Full disclosure i don't know what im doing. I have a very strong automotive background but always had someone tune the car for me until last season. Should i be concerned with the fuel trims? Where should I look for problems? i was thinking i could have an injector issue, but they were brand new ID1300s last year when apparently this issue was happening. Also, should I have LTFT on? on the advise of another tuner i turned them off, but i'm not sure why.