Sounds to me that if it quits in the air and then you need to wait a while before it starts again, it might be overheating.
In the air the plane will unload so whatever reading you get on the ground it might get leaner in the air.
I agree with the other member. Take cowl off and set all the needles factory settings. Low Needle 1.1 turn High needle 1.5 turns and go from there.
Also after one of those dead stick runs, did you look at the plug? The plug color will tell you a lot how you are running your engine.

Good luck.