I have a Thermador PG364GLBS/09. Been having bake issues; Replaced spark electrode and recently control board; Symptom was the ignitor was not sparking constantly; oven would heat to a point and then shut off; not spark; no gas; broiler and stove top work fine; I replaced the Master control panel; Now the oven still does not work. When I turn it on to bake tthe ignitor engages; you hear gas turn on and oven lights; as it starts to heat; it shuts down at about 200-250 degrees; blue bake and heating lights remain on; Randomly the spark ignitor will turn back on but gas does not. Any ideas?