I have a Coleman/Evcon sealed combustion downflow gas furnace forced draft with direct ignition (hot surface); I use propane gas.
The glow rod works and the pilot lights, but the ignition module clicks several times trying to light the furnace flame and then shuts down. It will try again with the same result.
I have replace the ignition module, the gas valve and the thermostat and still have the problem.
Any answers?

Clean the flame sensor with steel wool or sand paper.