I started to notice that my clothes weren't getting dry. They would be slightly warm, but would never dry. I tested every thermostat, sensor, etc that I could with my ohm meter and they all test normal (tested with wires pulled off, but still in dryer). Replaced the gas coils...no change. I turned the dryer on briefly with the door open to watch the burner. It fires up and will run fine with the door off. I placed the door back on and the burner fires up, runs for about 15 seconds, and then shuts off. It will fire up again in about 30 seconds, run for a little over 10 seconds before shutting off. As it cycles, the length between firing increases. Replaced the cycling thermostat (even though it tested normal)...no change. Any ideas? Do the thermostats, fuses, etc have to be removed from the dryer for accurate testing?

I haven't done that yet, but I did check where the vent exits the house and seemed to have good air flow coming out.

I removed the vent hose and it dried! Now what? Thanks!