Quick question for those who know.

My mechanical fuel pressue gauge has just gone stupid it fluctuates back and forward so fast I can't read it. My fuel bowls are level and constant. Think it may be a diapraghm issue?? What is good pressure anyway? 7pound???

Standard mechanical fuel pump.
Dual feed holley.
Ventilated gas tank.
Happens at all revs.

WEIRD!

Andy.