Sounds like itโs likely the igniter or the flame sensor. Another remote possibility is the high-limit thermostat.
You have probably already spent more than it would have cost to have a Tech diagnose the problem. Itโs time to stop throwing parts at it and use a multimeter and find the problem - then apply the fix. The sequence of operation should be in the Ownerโs Manual. Use it along with a multimeter to find what is happening and where the hang up is.
