Gas Water Heater takes 4-6 cycles before staying Lit

I played with mine for a year. Sometimes it would take 10 or more tries to keep it going. I cleaned the ingnighter with steel wool, re-gaped it, wrapped the insulator with teflon tape in case the was a small crack,and cleaned all 3 grounds. Atwood gives you a way to test the board with an ohm meter which I did and was good. I finally ordered a new ingnighter and installed it. It started right up the first several times I used it. After the 3 trip it still took 3-4 tries to get it to light.