Static and dynamic fuel pressure tests, hot, AND cold.
Static - motor off, fuel lines primed, note pressure, AND note pressure-let off time (post how long before it goes to 0). If it goes down too fast, you have leaking injectors, or a ruptured diaphragm in the fuel pressure regulator. Both will affect hot start.
Check the vacuum line to the fuel pressure regulator for a ruptured FPR diaphragm - smell the vac hose for a STRONG gas smell.
Dynamic pressure - gauge on pressure valve, motor on. Note continuous idle pressure, WITH vac hose OFF of FPR. Then put vac hose on, note pressure, then pull the throttle linkage, and note if pressure INCREASES. This is acceleration enrichment - response to increase vacuum, even tho' more fuel is pullin' from the line.
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