Sporadic fuel pressure. Normal?

[kristmen]

Having problems on a car.

Buschur Racing BR/SX AFPR with a B&M fuel pressure gauge located on top of the fuel filter.

Pressure was set to 40ish with the vac line pulled off and capped.

The pressure gauge sporadically bounced up and down. When I put the vac line back on the pressure dropped to about 37ish but it bounces sporadically up and down +- 5~10 psi. When I say sporadically, I mean sporadically.. The needle looks like its on crack and shaking.

Is this normal? If not, what causes it?

 

[99gst_racer]

That is definitely not normal. Your fuel pressure should sit still at idle; the worse I've ever seen was a fluctuation of 1-2 psi. I would first replace the gauge to rule it out as being defective or not. If the gauge is fine, then it is probably a defective regulator.

 

[kristmen]

Damnit Paul, I don't want to hear that.

Don't even have one to test with