Dryer heat not staying on GFDR480G

[trosser001]

GE GFDR480G is not drying closes well.  Heat sometimes doesn’t cycle on at all.  Other times it does, but quickly peters out.  
 

Checked vent door lint filter and all is clear from there through the dryer to wall vent and out to open air.  
 

Checked diagnostics via service mode, no error codes.  Outlet thermistor: 76kohm at ~88deg and inlet was at 75kohm at same temp.  Moisture sensor was at 240ohm.  
 

i haven’t yet measured the booster, safety nor the main coil resistance.

if the gas valve assembly is beginning to fail, would that explain heating that is sporadic?  

the heat at the exhaust port on the dryer is cycling on and off, even when I use the time-dry cycle on High.

and finally, if I give the rear cover a solid open hand slap when the exhaust is blowing cold air on a cycle that should be blowing hot air…low and behold the burner ignites!  But it then peters out.   Which makes me suspect the valve coils might be getting “sticky”.  
 

please let me know if my suspicion is viable, and if there are other justifiable conditions which might explain these behaviors (the dryer…not mine;). 
 

thanks in advance - tr

[16345Ed]

Be very very sure no airflow restrictions anywhere.  Most common cause of your complaint. 
 

yes gas coils fail in that way. They work when cold but after they warm up they open. 
 

Even on high burner has to cycle on and off can’t stay on whole time if would get way too hot. 

Edited December 19, 2021 by 16345Ed