Furnace Flame issues

Hi. Newbie here. I have a Goodman Furnace and just changed a very dirty filter. Iv noticed when the furnace is running It trys to ignit the burners and they stay lit for 2 seconds and then they go out. then it trys to ignite again and it lites for 2 seconds and then goes out again. it does this for the whole heating cycle. The fan runs for the whole cycle which it should. But the house maintains a constant temp. It just does not sound right to me.... Any ideas. The furnace is 4 years old.

Thanks for any Help.

I have some ideas but they would take a trained tech to check out. I would suggest you call a pro and if I'm right, it won't be an expensive repair. Sign up for a maintenance plan and keep it in top shape :D.