I'm new to the land of LS swaps. This is my second, the first one went good with no issues.

On this current swap but am getting a P0300 multiple misfire code. I've done plugs and wires. o2's appear to be working properly. I'm going to pull and clean the injectors next. Does anyone have any other suggestions for things to look for? it appears to be running without any hesitation or issues, i wouldn't know it was even a problem if the MIL wasn't screaming at me...