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I had the "hot start" problem return this fall. The fuel pressure also dissipates over a few hours after shut-off. The PO removed the stock fuel rail "trombone" pipes and replaced them with a single billet rail. There is a Summit Racing pressure guage on the rail. With engine started and running, there is approx. 29-30 psi. Without vacuum to the FPR- approx 36 psi. I knew that the loss of fuel pressure, over time, can be (a) leaking: - check valve in the fuel pump - cold start valve - FPR - injectors The pump is fairly new, so I added a Parker check valve down stream, between filter outlet and rail inlet. No change. The CSV was original, so I replaced it. No change. The FPR was for a '77-without the stock fuel pipes, there was a blocked off inlet. I found one online for $45, so I replaced it with a'78 model FPR. Tidier. No change. The injectors were original, though they had been refurbed/ flow-tested by an injector service in the last few years, the connectors were getting brittle, so I replaced with new- not reman- Bosch units. No change. The pressure still drops to zero after a few hours. So where else can the fuel go if it can't flow backwards to the tank/pump (check valve) and it can't return through the FPR and the CSV/ injectors are brand new? I'm stumped. The "hot start" issue- engine stumbles and seems to run rich for a few minutes after a 10-20 shutdown having come to full temperature (180) is slightly improved. Before the work done, it was a b*tch to start and keep running for several minutes. Now it starts okay ,just runs a little rough. So there is some improvement. The CTS/ thermotime switches are new, all connectors and grounds have been cleaned and protected ( Caig De-oxit/ dielectric grease, where appropriate). The AAR was removed by PO. Vacuum is within specs, AFM checks out (Atlantic Z bulletins). I welcome any suggestions/ thoughts. Thanks for reading.