Hi guys, I just installed a Superram and an Accel base on my 88 L98 Camaro. I put a new diaphram and BBK afpr on the fuel rail and I replaced the fuel pump with an AC delco pump about 4months ago. Anyways, the problem is first off with the fuel pressure regulator. If I have it set at 46 with the vaccum off and tighten the nut to hold the pressure there, it seems to jump to 50psi. Also if I barely turn the screw in the fp jumps by 5-10psi. Now when I finally set the fp at 46 and hook the vacuum back up, it'll go down to 42. Then after a few minutres it'll go down until its at 38. Then if I unplug the vacuum line, it fp reads 42 with no vacuum. Also, at WOT, the fp never reaches 42, it might climb to 42 for one sec but then it starts to fall back to 38 even while I'm at WOT. I am using a Nortskog fp guage and an electric sending unit hooked up to a 3ft line going into the schrader vavle. I have checked over all my work and have no idea what to do now. Any help would be greatly appreciated.

did you try the magical, all-knowing search key?

My guess would be that the AFPR is bad. Maybe the diaphram has a hole in it or there is dirt in there. Does it maintain pressure when the engine is off? How long? If your certain the FPR is good, I'd start looking at the fuel pump and the rubber hose connecting it to the hardline.

The fp goes down very quickly to about 12psi with the engine off then maintains that pressure for a while. I also installed 24lb injectors out of a 95 Camaro with about 80k miles on them. The diaphram was new and I can't see how an afpr could be bad. Just seems like its just a bolt that goes in and out, not much room for failure. I might try installing the old diaphram to see if that changes anything, but I can't see how the afpr could be bad so I'll keep that. Any other suggestions?

I will repeat my suggestion of do a search. Where the hell is that guy with the magnifying glass on the search button when we need him?