Turn on oven thermostat to 400°. Ignitor starts to glow and after a minute or two, burner ignites. Then oven goes into a cycle of good solid flame for about 1-2 seconds and it drops back down to hardly visible (as if set temperature was reached). Stays that way for 30 seconds and full flame comes back on for 1-2 second, and then down to minimal flame again. Oven never reaches set temperature and it takes forever to cook anything. So is the problem with the temperature sensor, the oven thermostat or the control wiring to the gas valve?

Then there's the issue of getting parts for a 27 year old stove...

Even though I just changed the ignitor about a year ago (previous one had no continuity and wouldn't glow at all), and being that this is about the only part still available I have a new one arriving today. I'll let you know how it goes. Thanks.

Update.... Thanksgiving morning I installed the new ignitor and now it works fine, and I get to play hero. Thanks again!

-Michael

Update -- Thanksgiving morning I replaced the ignitor and everything works fine and I get to play the hero. Thanks again!