Whirlpool Wall Oven WOS51EC0AS01 7 years old. Our oven has always heated slow in our opinion, and struggles to maintain temp after preheating. But now, preheat takes FOREVER. 350 takes about 45 minutes. Seems like in our test it took forever to get to 200 (35 minutes), then it went from 200-350 in 10 minutes. Broil works fine. I thought it was the bottom heating element - I purchased and replaced it, but the symptoms continue. Next, I went and checked the temperature sensor using the video from PartsDr, and it seemed OK. It was a little high on the Ohms test, instead of 1080 +/- 4.9, I got a reading of 1107. (I am wrong about this test? Is a difference of 27 ohms so far off that this is the problem?) So, now I believe the next step would be to replace the Control Board. But, that part will be $230+ with shipping. What else should I be doing to diagnose my problem? Would the experienced opinion be that it is time to change out the control board?