LG oven with F9 error but with a catch
I have an LG slide in range with gas oven and stove. The burner is the curved type in the back where the convection fan is. When we try to preheat the oven going directly to the bake setting, after awhile we get the F9 error. This happens every time we use the bake and try to preheat. BUT here's the catch, if we go to "Warm" and let it sit in this mode for 5 minutes or so, then switch to bake it preheats and usually works every time for whatever setting we want. This all started happening after we used a self cleaning cycle. Here lately however it seems as the problem is getting worse, and the oven now intermittently fails to preheat even with the warming method first. Any ideas? I have read often a weak igniter but I see glowing from the back even before the F9 code.