yo BB,
Try a Self Test for Diagnostic Trouble Codes (DTC)s by my pal, BroncoJoe19
http://broncozone.com/topic/14269-code-reader/?pid=74587&mode=threaded
A helper is good to assist in reading Codes; best is to take a cell fone vid and replay it.
Some basics;
Visual Check
Battery is fully charged & connectors and grounds are clean
Inspect the air cleaner and inlet ducting.
Check all engine AND HVAC (under hood & in /under dash) Vacuum hoses for damage, leaks, cracks, blockage, proper routing, etc.
Check headlights
Check EEC system wiring harness for proper connections, bent or broken pins, corrosion, loose wires, proper routing, etc.
Check the Powertrain Control Module (PCM), sensors and actuators for physical damage; can use these two diagrams to locate ACT, TPS, EVP above EGR), Ignition Control Module (ICM) on distributor mounted years (Ford re-located the ICM from Distr side to driver side hood hinge area on inner fender liner in 92-96); to MAP;
http://www.revbase.com/BBBMotor/Wd/DownloadPdf?id=14698
http://www.diesel-dave.com/vehic/manual/stj/stj31b21.htm
Sensor Locations Diagram ECT, IAT and Water Temperature Gauge Sender
Assuming no fuel leaks (also check near fuel injectors beside usual suspect areas;
seems similar to what I have seen in other 90-96 Broncos and Ford trucks w/single tank.
The in-tank fuel pump assembly has a discharge check valve (to maintain system pressure during shutdowns and to minimize starting problems), an inlet screen for protection and fuel return provision.
The Supply Check Valve, which is normally closed, opens when the outlet pressure from the energized pump exceeds the opposing check valve spring force. When the pump is de-energized (i.e., engine is shut off), the supply check valve closes to maintain pump prime and fuel supply line pressure.
Note: Maximum fuel pressure is obtainable at WOT or the vacuum hose removed from the fuel pressure regulator.
If fuel lines/systems have been drained or evacuated, it may take up to 15 seconds to obtain the pressure specified.
I believe the PUMP's check valve is Stuck in open (full flow) state and allowing fuel to return to tank, thus reducing fuel pressure while engine is off.
I have a slightly similar issue when first starting in morning or after long shut-down; engine will crank over normally, but not run or run rough at low RPMs until it runs or shuts down. If I hear it stumbling, I shut it off, then turn key to start; it will fire up immediately.
I may try a Ford type fuel cleaner soon.
This is by Ryan M; "After attaching the fuel pressure tester, run the fuel pump for 10 seconds. Check that the pressure is within specs, and it doesn’t leak down more than 5PSI within 60 seconds after pump shutdown."
FP;
KOER 30-35 PSI
KOEO 35-45 PSI
Note: Maximum fuel pressure is obtainable at WOT or the vacuum hose removed from the fuel pressure regulator.