new to z need some help with experience z owners! please

Ok so i finally had time to trouble shoot my z some more. After reading the efi bible and the some of fsm i checked resistance at cts.. it looks good. Looked a tps settings.. it leaves idle contact almost immediately and made contact with second thing about half throttle more or less. Then i checked timing and it was at 5 degrees so i advanced it to 7 as accurately as i could.. pumped some gas went for a drive and i feel like im still getting bad mpg but then again my gas gauge goes up and down so i wont be sure till im low. And i also need to pull plugs and clean them to bc they are still foul pretty badly. How do i go about checking if its a leaking cold start valve bc my oil still has a hint of gasoline smell...