I found I could "rap" on my broiler/oven control valve and the oven would light, so I ordered a new control valve. Installing valve was not difficult except for having to lay on the floor and work in a small space. After installation, the oven lit only ONE time...and the boiler/oven problem was unchanged....broiler would light, but not oven. (Both incandescent pilots would glow brightly, so I did not suspect the igniter/pilot.)
A friend suggested I swap ignitors anyway...and indeed, the fine print of the wiring diagram hints that the resistance of the glowing igniter is detected by the control valve before it will open.
So, I swapped the broiler igniter with the oven igniter and....VOILA! My oven works again!
Apparently my control valve was not the problem but since I installed it... it'll stay. ($120 probably wasted due to my mis-diagnosis.)
I plan to order a replacement igniter to replace the broiler igniter I borrowed.
AppliancePartsPros delivered my controll valve promptly and at a fair price. I will order from the igniter from them also. (The same part from Sears would take much longer to receive. AppliancePartsPros definitely beat the OEM in delivery and met their price.)