Hey guys, Ive taken a long break from my car but I've recently decided to try and get the LT1 running properly. I started having Solomon over at LT1pcmtuning.com tune the car almost 7 years ago. The data logs were showing the car running almost max rich on the right side. He said he could not tell if it was mechanical or not. What could be causing this? The injectors are not leaky, and there have been more than 1 set of o2 sensors on the car. There are no obvious vacuum or exhaust leaks. The engine seems to run fine. It idles smooth and also revs smooth. Occasionally after slowing down the idle hovers around 500 or lower and has stalled a couple times in the past. When it is really cold outside the car for lack of better terminology sounds like a galloping horse until warm. Just a really rough idle. Any ideas what else I can look for? Im going to pull the spark plugs today and look over the wires, but i need some ideas. This might be better in the tuning section?

Edit: Its been a long time but there may be a bad gasket match on the right side with the intake ports slightly larger than the gasket.

Thanks!