oven problems on my maytag gas cooking stove
 

Can anyone help me out with my stove problem? driving me crazy.
I turn on my oven and set it to a certain temperture. When it reaches
it's temperture, it shuts off like it's supposed to. The problem is
when we change the setting to a lower temperture.

example. we set the oven for 450. now we want to turn it down to 300.
well it starts to drop alright, but goes right down past 300 and then
it won't fire up anymore. The funny thing about it, is that it works
good sometimes and then doesn't other times. very intermitten.
Sometimes we have to wait a whole day for the stupid thing to even turn
on anymore.

One more thing, the broiler part of it, works great. no problems with
that whats so ever.

Thank-you