Gas dryer repair

gas dryer lites OK but will not get hot enough to dried load. replaced temp control switch but did no give me enough heat. can u suggest anything else I should check and what sequence. tumbler works, door switch also works fires up on high but and goes off shortly there after any suggestions? James Hazley desperate.

[RIGHT]Model Number:whiripool LGR7646JQO Brand: Whirlpool Age: 1 - 5 years [/RIGHT]
gas dryer lites OK but will not get hot enough to dried load. replaced temp control switch but did no give me enough heat. can u suggest anything else I should check and what sequence. tumbler works, door switch also works fires up on high but and goes off shortly there after any and reigniting ,suggestions? James Hazley desperate.