Intermittent misfire

[Jeffrey Dodson]

2006 Ford expedition Eddie bauer with 218k miles. After normal operating temperature it will start to shudder and act like it wants to die when I have to stop. Sometimes it will die. It restarts with no problems after. It's not bringing up any codes. Replaces all plugs and coils. Still doing it.

Help please! This is driving me crazy.

 

[Hamfisted]

How old is the fuel filter ? Check the FPDM (fuel pressure control module) back there on the frame at the left rear tire-well and see how corroded it is ( or if it's ever been changed...). The original ones corrode real bad and act up. The aftermarket ones have better bolt insulation bushings to help prevent the corrosion issue and save the module. Do you have any scanner that will read the fuel pressure PID in live data ? ( Something like ForScan ....)

 

[thesavo]

5.4L eninge?

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[SEPTIC PROFESSOR]

Authentic OEM Motorcraft plugs and coils or Chinese garbage knock-offs ?

 

[367KIX]

My 2003 always throws a code when I'm getting a misfire from a plug related issue. Given you had no codes, both before and after the plug/coil replacement, I doubt your problem is there. Even with "Chinese garbage knock-offs". I'm not familiar with the FPDM related fuel issues as my X with 230K miles hasn't had that one yet. Fuel filter issues usually result in fuel starvation under high demand like acceleration. Given this is occurring after warm up, I'd check the throttle body first to see if there is any crud built up that needs cleaning. Also check for vacuum leaks that can cause a problem after the fuel mixture adjusts for a warm engine. There is a common problem with a cracked vacuum tube at the top, near center, rear section of the engine, close to the firewall. Mine failed years ago, causing a similar issue.

 

[JExpedition07]

VCT solenoids that run the camphaser oil pressure supply, you will want to replace both solenoids if so as the banks phase timing equally. You can check them with a meter too. Lucky you 2006 model 5.4 3V valve covers do not need to be removed, on the 2007+ they have to come off to replace them.

Here is your $0 diagnosis test, unplug both solenoids (plugs that go into top of valve covers) and drive it and see if it’s cured. This will trip a CEL but won’t hurt anything. If it stops your stall conditions (I’m fairly certain it will) then you know!

 

[Jeffrey Dodson]

VCT solenoids that run the camphaser oil pressure supply, you will want to replace both solenoids if so as the banks phase timing equally. You can check them with a meter too. Lucky you 2006 model 5.4 3V valve covers do not need to be removed, on the 2007+ they have to come off to replace them.


Here is your $0 diagnosis test, unplug both solenoids (plugs that go into top of valve covers) and drive it and see if it’s cured. This will trip a CEL but won’t hurt anything. If it stops your stall conditions (I’m fairly certain it will) then you know!

This was the problem! Replaced them and havent had an issue since!