Heating igniter doesn't ignite
I have a Carrier gas heating system that is several years old. The electronic flame igniter (probably not the correct name) sometimes clicks repeatedly without lighting the flame. Then it quits clicking. I can get it to come on by turning the thermostat to off and then back on. It usually lights then. It may light flame OK through the day as the burner goes on and off but eventually doesn't work.
A service technician came out once and cleaned the igniter and it worked better, but still not all the time.
It probably needs to be replaced. Is this generally expensive? Can I buy the part and safely replace it myself?
Thanks.