Recently had my junk 5.3 go out due to lifters. It was already cammed so I went back with a 6.2 drop out. Had a stage 3 cam kit push rods headers high pressure oil pump and all the goodies done. Tune was set and ran good for the first few days. Then it started not cranking without throttle. This is only on initial start up. Can shut off and will start right back up. So it only does it in the morning going to work and afternoon leaving work. Assumed it needed some fine tuning for more fuel or air. Or like it has a bleed back fuel system. As I am no engine guru but know my way around vehicle. Took it back to the shop. Man said he missed a setting in the map sensor should be good. Great. Get there starts fine get home runs better. Next morning back to same thing. Tired of going back to the shop as it’s over an hour away so I’m looking for advice on the culprit. Is it the tune? Something bad part wise to check that may not be new? Again truck runs great once running only problem I can tell other wise is vibrating air filter box I believe. And again issue is only on initial startup. Give it some gas and it runs fine. Thanks for any advice in advance.