I had the same problem with very erratic fuel flow indications in my RV-14A, especially at higher altitudes where I like to fly in the mountain west. I finally got fed up with it and moved the red cube off the Vans RV-14 standard location on the engine. It's now mounted by adel clamp on the engine mount. Luckily I had enough fuel line slack to be able to move it there without needing to buy different length fuel hoses. The results were immediately noticeable. My fuel flow indications stabilized, and so far (about 20 hours since I made the change) everything appears to be working normally.