Hi All.
Like everything on. or in a Motorhome, it needs a good "Proventive Maintence Program Schedules". The more of it that you do due, the less problems you will likely have, over-all.
For me. anyways, I love to always tinker on our Motorhome. I'm almost in or doing something to our Motorhome on a dailey basis. Probably one of the reasons that we have never broken down in the past 45+ years as RV'er's. So far in the 45+ years, I have done all of my own work on everything that we have ever owned
Try a good cleaning first, then if it still doesn't want to work correctly, then have the Propane Pressure checked.
Good Luck. Happy Travels. Dan & Jill & Our Yorkie Kids