I have a goodman forced air furnace and it lights up for 5 secs... shuts down... 3 cycles of this and stops. I cleaned the heat rod with NO success and was just wondering if I should buy a new heat rod (where if so) or may it be another issue?
THanks
David

What heat rod? Are you talking about the sensor?

What heat rod? Are you talking about the sensor?
Yes the sensor rod

Usually the heat sensor can be cleaned but I have seen cases where they had to be replaces. Make sure the pilot orifice is clean.

If it wrere me I would replace the sensor and make sure about the pilot orifice.

You don't have to replace a flame sensor unless the ceramic around the sensor is broke and going to ground. Make sure the sensor or sensor wire is not grounded to the burners or furnace. If you have rust on the spade connection clean it to. Make sure the flame from the burners or pilot is hitting the flame sensor. With the newer furnaces the gas valve common wire also needs to be to equipment ground or the flame sensor will not work.

If you haven't solved the problem: Goodman/Janitrol is notorious for losing pressure around the gasket of the inducer housing. You can try removing the 5 screws that hold on the inducer motor housing and using some High temp HVAC caulk on the gasket and screw it tightly back on. Unless you have a micro meter you won't detect that the pressure switch is dropping of ever so slightly enough to break the 24v connection and then the gas valve drops off. I have seen this many many times before. If sealing that gasket doesn't work than replace the inducer motor. Good luck