1996 chevy c1500 5.7l LTFT RUNNING LEAN UNDER LOAD

ETCG.
AWESOME SITE, LOVE IT. ON WITH MY ISSUE. I HAVE A 1996 CHEVY C1500, 5.7L VORTEC ENGINE A/T. THIS IS A NEW FACTORY GM MOTOR WITH APPROX 600 MILES ON IT. THE ISSUE I AM HAVING WITH IT IS THE LTFT ARE RUNNING LEN ON BOTH BANKS 12 TO 14% LTFT AND STFT RUNNING FROM -0.8 TO 1.6 % ON BOTH BANKS, O2 SENSORS SEEM TO BE FUNCTIONING AS THEY SHOULD. AT IDLE THE FUEL TRIMS SEEM PRETTY NORMAL EVEN WHEN YOU RAISE THE RPMS. FUEL PUMP IS NEW WITH 62 PSI, i CLEAN THE MAF YESTERDAY AND THE LTFT WERE A BIT LOWER THIS MORNING UNDER LOAD BUT STILL HIGH 10 TO 11 % . MOST ALL OF THE SENSORS ON THIS ENGINE OR NEW AS WELL EXCEPT FOR THE MAF AND THE EGR VALVE. I ALSO HAVE NO CODES CURRENTLY. I RECENTLY HAD A NO START ISSUE WHICH TURNED OUT TO BE JUST A BAD DIST CAP, BUT IT TOOK A BIT TO FIND , WHILE GETTING TO THE BOTTOM OF THAT I DID PULL THE UPPER PELIUM TO INSPECT SPIDER INJECTORS AND FUEL REGULATOR, I DID REPLACE GASKET WITH A NEW ONE I HAD, AND RE TORQUE EVERYTHING TO SPEC . ANYWAY I WOULD APPRECIATE YOUR INSIGHT ON THIS ISSUE. I AM GUESSING IT IS GETTING UN METERED AIR FROM SOMEWHERE. THANKS.