We did a bit of travelling the past few days so added about 7 hours to the Arrow. A few flights ago I noticed what seemed to be a very slight vibration of my fuel pressure gage though no real movement that was discernable. Everything was runing just fine. Anyhow today while getting closer to home the fluctuation was getting obvious. I turned on the electric gage and the vibration continued though perhaps a bit reduced. Engine was still running perfectly. After landing at my home base I taxiied over to refuel and when at idle the gage was pulsating much more slowly with a greater movement so clearly something is wrong. Of course I'm going to get it fixed before flying again but am interested in the comments of the knowledgeable participants here on what is causing it and the best way to fix it.