ok I have a 2000 5.3 598/601 cam cai headers total rebuild bored 30mm stock heads 861 stronger springers valve job 1n stock tune it was running lean bank 2 25% at idle but normal under acceleration small backfire and stalling so I did a new intake gasket felpro new intake bolts with new rubbers new o2 sensors 8 new injectors and smoked it for 15 mins with no leaks showing (tune is on here under my name) I did a non maf tune off youtube and that helped bring Bank 2 lean to 9.5 but truck had no throttle response extended crank time and constant surge at idle 2: so downloaded stock tune again but bank 2 dropped to 9.5 lean and still is after stock tune so I can drive it now and did a log and it runs but has a small backfire and will not return to a stable idle cuts off it has power under acceleration and seems ok but not 100% vacuum gauge installed showing 10lbs at idle and(reads in red late timing vacuum leak or heat riser) I tripled checked for vacuum leaks and had engine 1 cylinder TDC PISTON UP dots lined up bottom of cam gear dot to top of crank gear dot 6-12 oclock tripled checked that during installation so im 99% sure that is ok can someone read this tune and let me know your opinion im beginning to think maybe pushrod length is wrong not letting valves close all the way I measured. with a adjustable push rod length checker I got stock length going by the method on almost every site about how to measure. ive had 30 yrs experience with sbc but this gen 3 is kicking my butt badly