Whirlpool LGB6200PQ0 gas dryer not staying lit

[DIY-man]

So I have a Whirlpool LGB6200PQ0 gas dryer that wont stay lit. Watching through the pep hole in the front of the cabinet I can see the igniter glow and the gas comes on and the burner burns a flame for about 3 minutes then shuts off. If left to run after the burner goes out, the tumbler still turns and the igniter will come back on every 3-4 minutes or so but no gas thus no flame. If I turn off the unit and let it sit for awhile I can get the burner to turn back on, but the same result happens as described previously. The dryer vent/duct has been checked and they are clean. I even pulled the unit out so the duct was straight to see if there was a restriction with the 90 degree bends in the flex duct that was maybe causing the high limit t-stat to kick off, but this didn't change anything. When the burner cut off, I tested the high limit t-stat when the burner cut off to see if it had continuity and it did. I have tested all the components for continuity and the solenoid coils ohm out correctly. I checked to see if the blower fan was turning and is good order, which it was. I checked to see if the blower air duct was clean and it is. I even tested the timer motor and points.... all checked out AOK.

All I can think of is that the solenoid coils are working when its cool, but for some reason not working when it gets warm. Please help me with this diagnosis. Is my theory correct or even possible? Or is it maybe the gas valve its self? I have no problem spending $15 on a set of coils, but if its not the problem I don't want to keep the wife and kids waiting on another part to arrive when the coils where not the problem.

Thanks in advance for reading my post and any help you can suggest.

[16345Ed]

It is a typical way for coils to fail. Once the get warm that is. 

Have you completed removed the duct and tested it? If it does the same thing with duct removed try the coils. 

[DIY-man]

2 minutes ago, 16345Ed said:

It is a typical way for coils to fail. Once the get warm that is. 

Have you completed removed the duct and tested it? If it does the same thing with duct removed try the coils. 

Yes, I did remove the duct and just let it exhaust into the room, with the same results. Thanks for your input. I will order the coils asap.

[Lighthouse]

Part number: AP3094251