I hope you find your problem. I have a similar issue but I have the Lex/550 mod. I found fuel puddles in my intake and I cant figure out why Im getting a super rich condition. Ive replaced my spark plugs twice already and Ive replaced the ISCV with a known working one too.
The only thing I havent done was send out my injectors to get tested, I shall be doing that soon as well.