Whirlpool Dryer Automatic Dry Cycle Not Working Over Drying

[DryerDIY100]

This forum and others like it saved me at least $500. I thought I would describe my issue and how I fixed it. I have a Whirlpool gas dryer that is 11 years old. I use the automatic drying setting using energy preferred. I have noticed it is running for an extended period of time. I consider it over drying. It can easily run for 2.5 hours. To the point that I would never leave the house with it on. In a nut shell it is properly drying and not turning off by itself. If I used timed drying it works. Troubleshooting 1) Cleaned the external exhaust pipe, no change 2) Opened the unit up and cleaned out the lint collection area and fan. It was 25% blocked still made no change. Now I had to buy some parts. Because the cost of parts are so low I decided to throw some parts at it without additional troubleshooting like testing continuity. The only rule I had is I would not replace the timer. I read too many posts on issues not solved by a new timer. 3) I replace the cycle thermostat, no change. 4) I replaced the gas valve coils. That fixed the issue. Here is what I think was happening. In the auto setting the timer only advances after it gets to the exact proper temperature. Weak coils prevented that from happening. I spent $15 on parts and few hours reading and troubleshooting. Thanks Everybody.