New ignitor measured 85 Ohm on connector pins using a general volt/ohm meter. The old Ignitor measured 240 Ohm at room temperature. (3 times higher than the new one!)
TIP: The Ignitor resistance can be measured from the back of the stove by disconnecting the (white) ignitor connector that is accessible from the bottom center opening at the back of the stove. This way it can be measured/diagnosed before doing any disassembly of the stove.
The ignitor is obviously connected in series with the valve for the gas supply to the oven. When Ignitor resistance is too high, the gas valve is not opening fully or not opening at all. Measuring the resistance of the Ignitor is a lot easier than measuring the voltage to the Gas valve, (as directed in some other tips to diagnose this condition.)
The ignitor is fairly easy to replace from the inside of the stove by unscrewing and taking out the bottom cover.
My Stove is now heating up in a fraction of a time it did before the repair, and is holding temperature as it should.