Just got done with an engine swap, and after the install the new engine had a rear main seal leaking. I took the car back to the shop that did the swap, and they replaced the seal and no more leaks. And no more Fuel Trims. Everything was fine before the trans came out to replace the seal Because I had been working on the Idle Air Flow tables Trying to get the car to idle. The first thing that crossed my mind was a loose battery connection. I did find a loose positive connection. I have not fixed the problem yet because I have to get a longer battery bolt. Any input ?