Not sure what model refrigerator you have (ours is a Norcold N621L) The 'F' fault code means the burner did not ignite or reignite. Since it does ignite while parked, it sure sounds like the airflow while driving is influencing things. And since it did work fine up until this point I would think the service tech would have checked gas pressure, combustion seal, electrode spark gap and cleanliness of the burner orifice (at the very least)
This is a link to a Norcold Service Manual that has a troubleshooting flowchart for various problems, including LP Gas Ignition Failure.http://www.liveworkdream.com/wp-content/uploads/2007/07/norcoldmanual.pdf
Generally, some of the things to check:
- Make sure the propane gas pressure is 11 inches of water column.
- Make sure the combustion seal is complete and intact.
- Make sure the burner and the burner orifice are clean.
- Make sure the electrode spark gap is 1/8 - 3/16 inch.
- Make sure the AC voltage is 108 - 132 volts and the DC voltage is 10.5 - 15.4 volts.
- Make sure the thermocouple tip is clean and secure.
- The flame should be a darker blue color on the inside of the flame and a lighter blue color on the outside of the flame, and a constant shape without flickering.
It should not be - yellow - flickering or changing shape.
- Make sure the flame does not touch the inside of the flue tube.
My manual describes the processes for removing and cleaning the burner orifice, examining the gas lines for leaks, etc. but also says these things should only be done by a Norcold Service Center.