My Whirlpool gas dryer ( 6 years old ) blow cold air after normal start working 5 minutes.
Check flame from panel hole ( normal ), no clog on vent,short hi limit thermostat
After flame cut off try to restart, I saw ignitor glow but after 3 second then go out, I have to wait for a while then whloe thing repeat again
Here is my question
How to check flame sensor or coli for the valve ( I saw someone post the same question
And fixed by replaced coil )

Need help and many thanks!!

Before we condemn any parts let's do a test. Start the dryer and observe the flame in the cone. Now stop the dryer. Remove the vent tube off the back of the dryer and start it again. Observe the flame again. Does it look the same? Does it stay lit for the same amount of time? If so or if I am misunderstanding your post try this test next. Start the dryer and let it cycle the flame on repeatedly. If after several cycles the ignitor comes on and goes out without the burner lighting you do need coils. The flame sensor is OK regardless since the ignitor is lighting and going out when the burner lights. If you need more help or if I misunderstood your post feel free to contact me again.

After replace pair coil ( $24.96 ) everything go back to normal, Great!
My lady give me a big hug seems like I am a hero

I want to thank Applsvcgirl faithfully to serve this site and very detail answer all the question, it's really helpfully , you are the man

Best Regard

David

Glad I could help!