Piper Arrow IV fuel pressure

This sounds like something that needs immediate attention. My guess would
be a leaking (or otherwise faulty) engine driven fuel pump or possibly a
leak in the gascolator.

On our Arrow IV, the fuel press gauge is stable in the middle of the green.
It moves just a bit (to higher pressure) when the electric pump is turned
on.

I think in your case a visit to the A&P is definitely in order. The good
news is that the problem is most likely not going to be terribly expensive
(in aviation terms) to fix.

Please let us know what you find.

--
-Elliott Drucker