Ive got a earls pressure gauge that screws into the dual feed line on a holley, the thing bounces around and sometimes reads 0. is there a way to clean or service this thing? its a liquid filled one and really hate to toss it. the car runs and drives so I figure its gotta be the gauge. Jim

Try blowing it out with compressed air or your mouth.

If you have a mech fuel pump, it will bounce around, espeically at idle. Readings will also be much lower when the engine is hot. There is probably nothing wrong with the gauge, thats just the way they are.

I had a fuel pump that was bad and caused the fuel pressure to bounce around a lot and go too high for the qjet carb. Maybe your pump is going out and the gage is telling you something.

I hope not its new, only got about 200 miles on it. JIm