We have replaced the distributer, plugs, plug wires, and the engine only turns over and will not start. We also noticed that fuel is leaking from the flange where the exhaust pipe meets the exhaust manifold. At our wits end with this one. The o-ring on the fuel pressure regulator is in great shape but not certain about the regulators condition. Could this be timing related, or a valve being stuck open allowing fuel to pass through?