I have a misfire at WOT. When I go to pass someone or cases like that. It doesn't do it any other time than when you are on it. It will just spit & sputter for a few seconds then it will finally take off. It almost acts like it is loaded up. Sometimes it sounds like it backfires when it is doing it. It will also blow out a lot of smoke out of the tailpipe.(white) It has thrown a code twice if you get on it 3 or 4 times right in a row. But it goes out within a couple of minutes and the dealer could not pull up a code. Of course I take it to the dealer to have it checked and it would not do it. Any other time it will do it on command.

2004 F-150
5.4L
New body style

 

White smoke is usually coolant getting into the cylinders. Are you losing any coolant?

 

I've checked coolant level it is normal.

 

White smoke is definitely indicitave of a coolant leak into the cylinder(s) and it doesn't take much. Time for a relative compression check on all cylinders until you can isolate the guilty culprit or at least the correct side of the engine. You'll see it---the cylinder(s) that spike(s) and bleed right out. Problem is your symptoms don't entirely match the profile--once your engine warms up, it should do it constantly...not just at rev....maybe you're just noticing it more at that time. What's the code?

 

I get a check engine light sometimes. It will go out though within a few minutes. The dealer said they couldn't pull it up because it is not a hard code. The smole is only when I am on it hard.

 

I've been told the same thing and I'm not entirely sure who to believe. To the best of my knowledge---if the PCM detects a problem for four consecutive drive cycles, it will set a code and cel and it IS stored. If the PCM no longer detects that problem for two consecutive drive cycles, it will clear the code itself. JMC and jbrew are good at this kind of advice---if you get a cel but it clears itself in a few minutes, I don't know if it stored it. I have read on this forum that if you suspect a problem, but get no cel, to get on the interstate, accelerate to about 65, and coast (no brake, no throttle) down to 30-35. Under these conditions, your PCM will run a full check and if it detects a problem, it will set and store the code and the cel. I have no idea if this works (almost makes me wish I had a problem so I could try it) or is a bunch of malarkey, but it's worth a shot.:santa:

 

I also have a 2004 5.4Ltr that misfires when passing or at WOT. I have always thought that it was the gas I was burning. As sometimes when I would fill up with the 10% ethanol blend (87 octane) it would do it much more often. I figured it took the PCM awhile to adjust to the different gasoline blends. However, this weekend while pulling a trailer I went to pass and it misfired about 4 times and did not like it. The engine light came on and blinked for about 60 seconds then went out. The engine runs fine other than when trying to pass or WOT. I have 80K miles & have had the fuel filter changed once (I think) and still have original plugs.

I thought it might be the fuel filter, but figured I would do a quick search on the website to see if anyone else has experienced this. Could it also be the plugs or injectors? My plan was to replace the fuel filter and purchase the high end fuel system cleaner for the injectors. Please advise!!

 

Mine does the exact same thing. (2004 5.4) More so when cold, but even at operating temp. I don't have white smoke, though. When I floor it from anything but a dead stop I get an exhaust pop and a brief stall and then the truck takes off. I have no idea why it does it, but it drives me nuts.

 

I've got the same issue... 05 F-150 Fx4 71000 miles and when running hwy speed and you give it just enough gas to kick down it will pop pop pop pop then go then sometimes start to pop again a lil higher in the rpm range.. I've tried running 3-4 tanks of super unleaded and no difference.

Took it to the dealer this am.. he is guessing plugs but will "check it out".

This started about 2k miles ago right after I had the vacuum booster line recall performed.

Country Punk your sig pic looks just like my truck minus my N-Fab bars

 

Well my compliments on a bad *** truck loop! lol

 

well got the call.. $700+ to do plugs, diagnostic, and reflash pcm. Now $92 of that is to reflash the pcm which I called bs on. Told the guy the reflash seemed a lil high - didnt mention my edge tuner I have at home - so calling around for quotes

 

The first things to check with misfires are plugs and coils.

 

i have my 5.4 2004 Screw miss when i hit it to pass cars on freeway. my DTC code was P1281 they told me it was the Fuel Pressure Regulator you might want to check that. i am switching mine out this weekend. i have 67K on my Screw, looking to do the plugs soon.

 

I finally got the codes to stick.

Cylinder #1 misfire
Lean condition

I thought maybe it was the coil on #1 cylinder, so I bought a new coil and it still does it. No corrosion or signs of water around the plug.

Could it be an injector? or a plug that needs replaced. The truck only has 55K miles on it.

 

My 06 does the same damned thing. (no smoke, though) Stumble and backfire, hesitate, then go. It really sounds great doing all that crap thru the magnaflow exhaust!