Hi folks, bought an older home last year with a Garland G283 gas range - double oven, six burners, griddle, and broiler. Burners, griddle, and broiler all work well but the ovens don't maintain temperature.

I hooked up the thermometer I use for smoking to it this evening and charted out the temperature in one oven. When I set the oven to 300 degrees the saw tooth pattern of the oven cycling had 300 degrees at the top of the saw tooth (seemed to average cooler than set). When set to 400 the pattern had 400 in the lower third of the pattern (seemed to average hotter than set). When set to 500 the oven hit about 480 then averaged around 475, never hitting 500. Finally when set to 425 over about 30 minutes it dropped to 417 and then climbed all the way to 450 then dropped back to 430...

I can post a graph if that will help. My thought is that the thermostat must be shot given that the temperatures were all over the place. Does that make sense? Anything else I should check?

Appreciate the help!