Engine leaning out at 3000rpm

It does it hot or cold it never did it before i started messing with the valley pan the car rod around all over the place like 2 hour trips and stuff never had a problem i had cracked the base plate on my quickfuel and thought that was it thats before i had the torque specs and i was cranking that thing down like a champ so i tried my buddies brand new 750 hp just to see if it would give the same symptom it did with a new set of gaskets and the 80inchlb torque spec the car went from haulin *** and being awesome to this shortly after the intake valley pan swap it has to be related but i cant get no leaks from the top side eith ether propane carb cleaner etc so it must be leaking on the under side maybe ive read performer rpms being tight on the top and gapped at the bottom but you think that woul cause it to idle high or something or just drive like crap all the time thank you for all your input by the way i appreciate everyone who tries to help!