I have a 98 ford f150 5.4 rebuilt engine never had a problem like this before all of a sudden I have hard start issues but if I use starting fluid it will start but after that 30 secs to 1 min I turn it off and then turn it back on no issues no problems the rest of the day Ive replaced the IACV (Idle air control valve) the temp sensor the map sensor no I'm lost and don't know what else to do can someone, anyone please help I have to leave for a trip Sunday morning I need this to be running perfect oh by the way there is no codes being thrown by the ECU........HELP

 

If you haven't I would change the fuel filter first. Sounds like you might be starving for fuel until the fuel system gets up to pressure. It would explain why the starter fluid helps initially. Just my two cents.

 

It sounds like the fuel check valve is leaking, causing fuel to leak back into the tank. To verify this, try turning the ignition switch to the "run" position for a few seconds, then back to "off" a few times. Then try starting.

 

hey thanks for the info where would one find this check valve

 

Hi Brad, I believe it's on the inlet of the fuel pump located in the fuel tank. I do
not know if the check valve is replaceable, or the fuel pump has to be changed.