I have a gas dryer, when I turn it on the gas kicks on but when it cycles off it doesn't kick back on and the clothes don't dry

CHECKS UR THERMOSTATS AND UR VENT LINE FOR CLOGGING. MY GUESS UR CYCLING THERMOSTAT OR THERMISTOR

My whirlpool dryer Model GGW9896KQ2 seems to run ok but it doesn't seem to heat up properly and takes several cycles to dry clothes. I checked the exhaust vent and it seems to be blowing air out ok. Also, it appears the dryer goes to the cool down cycle way to early. In addition, the dryer will sometimes shut off before the time is acutally done. help--I don't want to spend money for a tech or even a new dryer. It's only 8 years old.

If the flame come on to start with, but then goes out and won't come back on I would suspect you have a bad coil on the gas valve.
If you see the flame cycle on and off, but the flame does come back on again this is normal. The flame needs to cycle on and off and not be on steady or the dryer would get to hot.
If the flame is cycling ok and the cloths just don't get dry then you need to check your dryer and vent for lint build up.

check the thermocouple, If the thermocouple is bad the burner won't ignite.

http://www.repairclinic.com/Dryer-Repair-Help

There is two possible causes. Either your gas coils are going bad late in the cycle or your venting is restricted. I would go outside check to make sure you have good airflow. If you have good airflow outside the only common cause of gas dryers failing to heat late in the cycle would be gas coils. If you have a peep hole on your dryer look in it after your dryer has been running for approx 30 mins and see if the ignitor glows and then shuts off. If the burner does not kick on then you have bad gas coils. They are part number 5303931775.

Let me know if this helps _MJ_

I am having the same problem on a WD9900A. The wash cycle works great. Spins fast and clothes are completely rung out. Dryer cycle heats up well. Fluffs and heats cloths. At some point during dry cycle water is injected on clothes and they end up sopping wet; much wetter than after wash. Filter is clear. Outlet pipe clear and functions well. Possible problem with dryer timer? Or washer timing kicking back on?

Replace both coils on the burner valve . After heating up , they will not open to let gas thru again until cooled down for a short period of time . With no heat , timer will not cut off unless set for timed dry .

Consider a blocked air flow/vent problem or bad gas valve selonoids. Important to check outside vent door if present to make sure it is opening all the way. If not the dryer goes off on thermal overload. If vent is clear consider selonoids located on top of gas valve held in place with 2 philip head screws. One has a two prong electrical plug and the other has a three. Last check Lp tank for gas. Thank you

replace both coils on the gas burner (the round black dohickeys)after first ignition they tend not to pull valve open next time heat is called for