Furnace troubles

Hello there, my first post... so I have an old 5th wheel trailer I have been fixing up, a '84 alpenlite 28'. So, I tried to get my furnace running, first of all it was missing a ignitor/flame sensor-so I got one an installed it. So when I tried to fire it up it would light for a few seconds then go out. So I figured the flame sensor was not sensing flame. I figured the whole darn thing needed a cleaning and inspection, so I removed it and cleaned up contacts, tested the sail switch & high limit switch, blew out the burner area, cleaned the gas tube & orifice, and tested the soliniod/gas valve. Everything tested good. So next I tested my actual gas pressure and it was low, so I got a new regulator and retested. I now have 11 inches of water ccolumn with other devices running. So I tried to fire up the furnace again and after all the air bled out of the line it fired up and ran fine for a few min then the flame went out. So I turned the thermostat off and on again and it fired up for a few seconds then the flame popped loudly a few times and wouldn't relight. I did this a few different times until it popped really loud and blew a chunk of my flame sensor gasket out. It is a atwood/hydroflame model 82. What could cause this? Flame sensor/ignitor alignment? It is brand new... circuit board issues?(it's the only thing I can't test) Soooo, now I come to the experts for advice!