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Need help with Ford 5.4 misfire

rholbrook

Premium Member
Supporting Member
Location
Kaysville, Ut
@TRD270 Are you sure its not tranny problems? I mean, I know what a misfire feels like but I had a tranny in one of my 5.3 F150s that did goofy things. I would take it in and Ford would reprogram it and it would be fine for a while and then start doing it again. The tech told me that the computer tried to learn my driving habits and adjust to it. They would literally disconnect the battery for a bit and let it reset which did most of the change but then flash it as backup. They thing that really was weird is that it would go from overdrive to a lower gear and then bang back into overdrive and it felt and sounded like someone would rear end me. A couple of times it would shutter like it was a misfire.

For shits and giggles, if you haven't done it, disconnect your battery for 30 min and see if that does anything. I know it doesn't sound logical but at this point, give it a try.
 

TRD270

Web Wheeler
Location
SaSa Sandy
@TRD270 Are you sure its not tranny problems? I mean, I know what a misfire feels like but I had a tranny in one of my 5.3 F150s that did goofy things. I would take it in and Ford would reprogram it and it would be fine for a while and then start doing it again. The tech told me that the computer tried to learn my driving habits and adjust to it. They would literally disconnect the battery for a bit and let it reset which did most of the change but then flash it as backup. They thing that really was weird is that it would go from overdrive to a lower gear and then bang back into overdrive and it felt and sounded like someone would rear end me. A couple of times it would shutter like it was a misfire.

For shits and giggles, if you haven't done it, disconnect your battery for 30 min and see if that does anything. I know it doesn't sound logical but at this point, give it a try.

Thats the funny thing is it drives fine and really smooth. Transmission feels fine. I wouldn't even know there was a misfire if the computer wasn't registering it. Every once in awhile it will feel like its idling rough but for the most part its super smooth. I'm open to ideas though, i'll try the battery thing.
 

TRD270

Web Wheeler
Location
SaSa Sandy
Well fuel filter is changed, no testing yet but i'm going to say probably not the issue. Pretty much no resistance when blowing through it.

Still need to check pressure
 

TRD270

Web Wheeler
Location
SaSa Sandy
Well more frustrating news. Fuel filter had no change, went on my test loop, more of the same pretty much nothing around town, or under acceleration but soon as I settle into highway speed misfires away.

Also found my local orielly to have a fuel pressure test rental. 30# key on, 30# at idle. 35-38ish pounds on the freeway. Never drops when I hit throttle. Regulator works fine as pressure went to 40 when I unplugged vacuum.

I'm at a loss, and really want to set it on fire.

Also burnt the shiz out of my hand on the EGR trying to pull vacuum line off the regulator so that was fun.
 

TRD270

Web Wheeler
Location
SaSa Sandy
Any more thoughts? ECU? I'm surprised how cheap the computer is. Probably cheaper to replace it than to take it to Ford for a diagnosis. But if its not the computer then its another $200 down the drain. Not sure what else it could be though.
 

mbryson

.......a few dollars more
Supporting Member
Any more thoughts? ECU? I'm surprised how cheap the computer is. Probably cheaper to replace it than to take it to Ford for a diagnosis. But if its not the computer then its another $200 down the drain. Not sure what else it could be though.

What year is yours? I was ALARMED at how much was quoted for the 2010 V10. Then it supposedly needed dealership programming to work
 

Kevin B.

OLAF
Supporting Member
Location
Stinkwater
Any more thoughts? ECU? I'm surprised how cheap the computer is. Probably cheaper to replace it than to take it to Ford for a diagnosis. But if its not the computer then its another $200 down the drain. Not sure what else it could be though.
I don't know if there were any differences between 00 and 01, but if you want to spend a Saturday frogging parts I'm game.
 

TRD270

Web Wheeler
Location
SaSa Sandy
What year is yours? I was ALARMED at how much was quoted for the 2010 V10. Then it supposedly needed dealership programming to work
2000

I don't know if there were any differences between 00 and 01, but if you want to spend a Saturday frogging parts I'm game.
I think i'm going to bite the bullet and pay the stealership $130 for their diagnosis before I drop coin on a computer.
 

TRD270

Web Wheeler
Location
SaSa Sandy
Double check for leaks in the intake tube, extra air can also make the trims move around a bit.
I sprayed carb cleaner over everything on the top end, no change in rpm
 

thenag

Registered User
Location
Kearns
What year is yours? I was ALARMED at how much was quoted for the 2010 V10. Then it supposedly needed dealership programming to work
Yes when I thought I might have to do a new ECU on my 07 v10 that is nuts.
Ford Tech Makuloco shows how to trick a junk yard ECU into working in one of his great videos, you need to have a dealership quality OBD2 machine. Maybe you could convince a dealer to do it for you, who knows.

Sorry for the useless sidetrack.

Nathan
 

thenag

Registered User
Location
Kearns
2000



I think i'm going to bite the bullet and pay the stealership $130 for their diagnosis before I drop coin on a computer.
I had a bad time at Larry Miller Super ford, their entire shop kept wanting to charge me $1300 to inspect the timing set. It turned out to be an electrical issue, their wild ass guess wasn't even in the ballpark.

Nathan
 

TRD270

Web Wheeler
Location
SaSa Sandy
I had a bad time at Larry Miller Super ford, their entire shop kept wanting to charge me $1300 to inspect the timing set. It turned out to be an electrical issue, their wild ass guess wasn't even in the ballpark.

Nathan
Good to know. I refuse to do business of any kind with a dealership that has LHM in it.
 
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