It all started with the timer not advancing on automatic dry. Clothes would be sort of dry. Dryer didn't stop by itself. I cleaned the vent and the burner area and the flame sensor. Worked the same. I tried the timed dry cycle. Clothes sort of dry after 2--90 minute cycles. I tried running the dryer without vent piping to outside...didn't make any difference. Pulled the front off again and checked thermal fuse and high limit t-stat for continuity. both ok. ran dryer with front off and lint duct off fan. Runs, lights stays lit for awhile, & flame goes out as if to cycle, and doesn't light again. flame senor works, red wire to gas valve has 123 volts, won't light. I'm thinking gas valve coils. Please advise, I'm stuck.

dave