So right, it might simply be lack of damping in the fuel pressure gauge and I'm with you that I'd be shocked that the OEM gauge itself is that imprecise as well as inaccurate. Many folks don't know the difference. A precise but inaccurate gauge can be calibrated to be made accurate, whereas an imprecise gauge really needs to be thrown away. People on here are simply dismissive of the OEM gauge but many are very experienced too, so I don't really know what to think.