Whirlpool gas oven not staying maintaining temperature

I have a 10 year old Whirlpool gas oven (model SF367LXSB) and it isn't keeping temperature. I will ignite every time but and usually gets to temperature after about 25 minutes. Sometimes I click stop and then restart the oven trying to get it to temperature. After a while the temperature slowly drops to around 200 or lower.

I replaced the valve last October with a whirlpool valve. I replaced the temperature probe this past weekend. The problem is still there.

I am not sure what to...

Whirlpool gas oven not staying maintaining temperature

via Whirlpool gas oven not staying maintaining temperature
by kubie