Dr Quick wrote:
Have you checked the "flame"? Sometimes dirt or scale can fall on the flame outlet and interfere with the flame. Make sure that it is working properly.
Also wind inside enclosure, could be interfering with flame. On my previous trailer I had to wrap come aluminum foil around flame enclosure, otherwise it would blow out when moving. The problem actually developed a few year after I got trailer.
I don't think it is wind interfering with the flame since I have the same result on 120 V (running the generator). The flame has a cover which would make it difficult to respond to wind but I could try wrapping the cover with foil to see if this improved the operation when traveling on gas.