I had a similar issue with no check engine light or trouble codes.
My issue was on first start of the day; starter cranks normally with ignition key, engine turns over with slight, hesitant stumble @ low RPMs for no more than a few seconds then engine gets up to fast idle and runs well. It runs and starts as new the rest of day with shut-down periods running from 5 mins to 4 hours. Lately, it is starting like new.
Try some fuel system cleaner.
The in-tank fuel pump 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 fuel pump is de-energized (i.e., engine is shut off), the high pressure pump supply check valve closes to maintain pump prime and fuel supply tube pressure."
The in-tank high pressure pump supply check valve is not repairable or available.
But others have installed the check valve in the fuel supply line. But none provided the source or part number, ever.
Item Part Number Description
1 — In tank Fuel Delivery Module (Part of 9H307)
2 — Supply Check Valve (Part of 9H307)
3 — Venturi Filter Screen (Part of 9H307)
4 — Pump Filter Screen (Part of 9H307)
CHECK FUEL PRESSURE LEAKDOWN:
Observe the "Notes, Cautions and Warnings" to avoid fuel spillage and injury.
Connect the Fuel Pressure Test Kit at the fuel pressure test point.
Connect a jumper to the FP lead of the DLC.
Key on, engine off.
Ground the test lead using the jumper wire to run the fuel pump.
Run the fuel pump for 30 seconds minimum.
Remove the test lead ground and note fuel pressure on the gauge.
Verify whether the fuel pressure remains within the specified 5 psi for 1 minute after the test lead is ungrounded.
4.9L 45-60 psi
5.0L 30-45 psi
5.8L 30-45 psi
Key ON Engine OFF:
4.9L 50-60 psi
5.0L 35-45 psi
5.8L 35-45 psi
Pressure Test Gauge Overview "...To test the fuel pressure you'll need to screw the tester onto the schrader valve on the top of the fuel rail, it looks like a tire air valve stem. After attaching the fuel pressure tester, run the fuel pump for 10 seconds. Check that the pressure is within specs, and it doesn't t leakdown more than 5PSI within 60 seconds after pump shutdown..."
check a loan a tool program at local parts store.
Try a Self Test for Diagnostic Trouble Codes by my pal, BroncoJoe19
The engine temperature must be greater than 50° F for the Key On Engine Off (KOEO) Self-Test and greater than 180° F for the Key On Engine Running (KOER) Self-Test.
Run it around to heat the engine up and shift thru all gears including Reverse.
Make sure A/C is off and transmission is in Park (automatic); or in Neutral for a Manual & release clutch.
Then turn off engine, all accessories/lights (close driver's door) , etc.
Do KOEO test First
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