Weird fuel trim issue....need opinions

[Cozmo2806]

I have this weird issue of fuel trim difference between bank 1 and bank 2. Ill start it and the difference between bank 1 and bank 2 is substantial, 10-15% different from each other. Ill let the car run for a bit and they even out to an acceptable difference. Any thoughts....log and tune attached

Thanks

sportsn95final.hpt

stftbankdifference.hpl

[mstang_man]

Your Calibration is a Crate Calibration. check to make you dont have any vacuum leaks on Intake manifold or Vacuum lines, check make sure no leaks on the exhaust manifolds. you may have a Lazy O2 sensor if there are no leaks present. Any DTC codes? Maf needs some work down low.

[Cozmo2806]

Your Calibration is a Crate Calibration. check to make you dont have any vacuum leaks on Intake manifold or Vacuum lines, check make sure no leaks on the exhaust manifolds. you may have a Lazy O2 sensor if there are no leaks present. Any DTC codes? Maf needs some work down low.

Did my vacuum checks and we are good there. Eliminated all vacuum lines for the time being. Took the manifold off and triple checked everything. No codes, but I did forget to check for them before I flashed the ECU again. Haven't had any luck dialing in the maf too close as the trims have been all over the place. Tonight I did swap the o2s from side to side to see if the problem followed the o2. Did a quick log and now they are much closer. It may have been a bad connection on one. Need to do more diagnostics and logging as I'm not 100% confident it's fixed just yet.