I have an 8 year old AO smith Power House Power Shot model MF03-2528832-270 hot water heater (pilotless)

Everything seems to work as normal, glow plug lights up, gas valve turns on, flame ignites, and then the burner comes on.
The burner stays lit for about 5 seconds, then goes out.
It repeats this process 3 times, then quits trying and goes into vacation mode.
If I continue to turn it off and on, eventually the flame will stay on, and I'll have hot water for another day.

I have a multimeter, o-scpoe, misc other tools, and a strong electronics background if that helps. Can someone point me in the right direction?
Thanks

I had the same problem. A guy came out and cleaned the area underneath... a screen area. He said it was very easy and would show me how to do it in the future, but I wasn't able to be there. It's happening again now so I'm trying to find out what the part is called that he cleaned. But, if you can figure it out from here you'll be fine for about a year. Our area is a little dusty and seems to affect it. Keep the area clean and you may be okay.

Follow up. I just found the name of the part that was cleaned. It could be a dirty or grounded flame sensor.

And here's a link to some good tips. http://www.doityourself.com/forum/water-heaters/221664-5-year-old-o-smith-50-gal-gas-water-heater-wont-heat-regularly.html