I have '03 Tahoe it idles fine but shuts off in gear

I just changed mass air flow sensor. No help there either. I do have a manual, but I don't know where reset button is. I checked everywhere for vacuum leaks. Found 0. This truck only shuts off when warm and you apply the brake. Oh and while changing alternator the battery was disconnected. Please help. Don't want send to a garage and get charged a zillion dollars that I don't have. Truck was running fine , except recent antifreeze leak that's not present on the ground. New battery new alternator new mass air flow sensor new serpentine belt.

@tennisshoes. Try that no good. However when stepping on pedal in park it paused and then sounded like a vacuum leak. Gonna try changing intake hose don't see any leaks but when I pressed gas pedal in park a buddy told me that where sound came from.

@tennisshoes. Do you think it could be the throttle body? I went through every gear w/o truck moving and it finally shut off. Before I would drive it and after warmed up it would shut off while pressing brake. Today I shifted into each gear with out moving a @ each shift idle went down until eventually shutting off. Actually question posed to anyone.