Furnace will fire up and run about 15-20min and I get a burnt smell through the registers. The furnace then shuts itself down. If I shut off all power to the unit and then flick the igniter switch a couple of times, the unit will fire back up and do the same thing all over again.

Any ideas?

Never mind, it's fixed. Called the repairman-Chris Hunt from National Heating in Jackson, Michigan. He diagnosed the problem as the capacitor hooked to the blower motor and the smell I was getting throughout the house was the blower motor getting extremely hot. Luckily, my blower motor is still good and the capacitor was only $5. Service charge was $85, which I felt was really fair considering it's a 40 minute round trip from his home office and it took him 45min to diagnose, change the capacitor, and he cleaned the flame sensor/rod too.