We have a built in wall oven, propane gas. Back in June we had issues, had an appliance guy out, he replaced the ignitor. Oven worked good for a while.. Now, issues again and he came out today and was there for over an hour, couldnt figure out what was wrong. He replaced the ignitor, the ignitor lights fine. When you first put the oven on, it heats up to temp and pretty quick too, like it should...then when it gets up to temp, the ignitor goes off as it should.once it loses temp again, the control panel (or whatever part) makes the ignitor come on, but it wont "relight" the burner. You can hear/smell the gas. He cannot seem to figure out what is wrong HELP ...