Have a Heil furace in garage start up blower start glow plug starts burner come up to temp fan starts may run for 2 min to 5 min. shuts off before it get up what the themostat is set at it will keep doing this cycle.What could be something to check?

Capicitor that goes to the blower fan would be the first thing,, they are cheap, get exactly same numbers like the one you have,, if this don`t help,, let us know

Clogged air filter? Something blocking air return or supply?