I have a York Stellar Furnace The Model Number is ( P3UCd20N09101A) I can not get the flame to stay on, Therefore I am heating my house with the oven . I have cleaned the Temperature control stick, Gas is on, Thermostat is digital and has new batteries, and the filter is brand new. I have vaccumed out where the burners are and have generally tried to clean all the other controls. Still no heat. Do you have any other ideas that I can try before I have to hire a repair man. Thermocupler? Piolot adjustment? etc..

That sounds exactly like a dirty flame sensor. If you cleaned already clean it again. Steel wool or sandpaper with a bit of elbo grease if you follow my drift.