The dryer heats up at the start of the cycle then the burner cycles off (in a few minutes), the burner tries to re-lite. The heat element (igniter) starts to get hot and then cuts out before the burner comes on. The vent is disconnected and I have tried both the timed dry cycle and using the moisture sensor cycle with the same results. All sensors have been cleaned along with the exhaust vent. Thinking it might be the "Heat boster coil" that is located by the thermostat.