Load a stock tune with LBZ FPR scaling and see if it runs fine, it says "barely running" with no real description....
A stock LB7 file with the correct scaling to idle smoothly, in a sac 45 injector truck will run about like a "tow tune" in a stock injector truck.
If not then there is other issues that need to be looked into. As far as codes what are they? Generally codes cant point you in the right direction of the issue.