Bank1 unstable fuel trim

[projectpanda]

I'm trying to chase down the cause of my unstable Bank1. Bank2 looks stable.

I recently just put in a replacment engine. engine starts up every time, and idles fine, it runs very rich at idle. No CEL at all also.

I'm on the same tune as my previous engine, and have added headers now.

Things I have done:
-smoke tested the intakes and plenum for leaks. Everything mostly checks out, I do have some smoke coming from the maf from both bank1 and bank2. i plan to swap the maf from bank1 to bank 2 and make sure the seal is in good condition or replace it with a new one. Voltage for both MAFs are also consistent which makes me believ eits not the MAFs.

-Had an exhaust manifold leak and replaced the gasket. but problem still exist. made sure the test pipe to header flanges didn't have leaks and rtv them to make sure.

-replaced the spark plugs with new oem. swapped igition coils from bank 1 to bank 2 and still same problem.

-replaced the pcv valve

Next things I plan to do:
-swap the upstream o2 sensor. these are new Denso sensors also, but will swap bank1 to bank2 to see if the problem follows

-pull the fuel injectors to check o-ring and swap bank 1 to bank 2 also. injecors were sent off to be cleaned not long ago.

-read somewhere that the downstream o2 sensor somewhat sends a feedback signal and was a cause of some people's bank issue. I have test pipes with defoulers and have never had any problems previously. I will unplug them and see if it affects anything.

I can't think of anything else