Rudd Heater Flame does not stay lit- new sensor

[wburger1]

My flame comes on for a few seconds and goes off. I have read lots of forums and they all say to clean and or replace the heat sensor. Well I took it off and it looked brand new so I cleaned it anyway. Then after a few attempts it started working. Ordered a new sensor just in case. Today it did the same thing on for a few seconds and then off. Replaced with a new heat sensor. Did not work. Tried it seversal times and now it is working. I do not want to do this everytime it gets cold here in Texas. Any ideas. Hate to buy a new circuti board as it was just replaced two years ago for an A/C problem. One other thing. When it starts working the flame LED flashed on and off for about a minute and then stays on.

[wburger1]

RUUD Silhouette II gas furnace. Model Number is UGPH-10EBRJR