Rough idle '95 Ford 460, distributor & fuel injected, ideas?
It's a Ford 460 engine. It's a seldom-used camper. Sometimes it bogs down and nearly stalls but it randomly misses on cylinders at all rpm's. I've changed out and examined all the usual suspects. One clue is that the vacuum pressure coming from the upper intake manifold seems very strong, rattles the crap out of the (brand new) PCV valve, and when I disconnect this vacuum connection partially at the intake manifold (plenum) it idles up, sounds better, but still skips cylinders yet you could drive it. The vacuum connection is a T connector and I will follow the other line direction under the vehicle next.
I have replaced/checked all the following:
Air & fuel filters, oil.
Fuses and relays.
Ignition Control Module***
Plugs, wires, coil, distributor.
Voltage regulator, alternator pigtail.
Alternator tested OK with the old regulator.
10uf, 63V capacitor in the PCM.
Replaced cracked vacuum lines.
Replaced mashed EGR valve gasket.
EGR valve not sticking but,
the connector reads no volts.
MAP sensor.
No MAF sensor on this model.
Fuel pressure regulator.
Ran Lucas injector cleaner.
Cleaned every electrical connection,
ground wires especially.
No sabotaged oil or gas.
thermostat, lower intake manifold
*** Ignition Control Module replacement is gray instead of black. Not right?
No
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