Car Information:
Ford Bronco
Year: 1993
Engine Size: 5.0
Trans: Automatic

Issue / Question:
I can start my vehicle cold, allow it to warm up, and then drive it all I want. Easy throttle or full throttle–it doesn’t matter; it runs great with no misfire. If I shut it down and restart it, it has a misfire that seems like it is random cylinders, but not only one. Fuel pressure is good (36 PSI at idle and 40+ PSI with throttle) and regulator is good. It has new wires, plugs, distributor and coil. No vacuum leaks werefound. Timing is set at 12BTDC and plugs are gapped at 48. I am stumped. Please help!

Answer:
Pull the vacuum hose off the fuel pressure regulator and see if it is leaking fuel into the intake. If that doesn’t seem to be the problem, do a residual fuel pressure test with return line pinched or plugged to see if the pressure drops. If it does pinch off the supply line then injectors are leaking fuel and fouling cylinders. If it sits overnight it has time to leak and dry out before restarting.

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1432 Lee Road OrlandoFL32804 USA 
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