Having some trouble with a 06 5.4L 3V Triton engine. When you step on it hard, wide open throttle, the truck will sputter and hesitate. It only does it once fully warmed up. I was able to floor it tonight and it was acting as if there was a misfire and then after a little while it seems to pick up and then rev up.

Scanned the computer, 0 codes. No past or present codes
O2 Sensors are reading fine
MAF is registering
Air Temp Sensor is reading fine
Vehicle temp normal

I read a few posts about a problem with the air filter gasket which I fixed but it didn't help.

When cold, seems fine, ht the gas revs up in gear out of gear, load no load...
When it starts to warm, you'll hit the gas and feel a real subtle hesitation
when fully warm, you can hold the pedal to the floor and it will pop pop pop like a misfire or really feels like a flat spot in the carburetor, I was able to have it stuck doing it for a good few seconds. (I know it doesn't have a carb, just feels like a flat spin in a carb.)

When driving the same thing if you step on it hard it may do the same thing.

I am going to pull a plug or two tomorrow to see what they look like.

06 with 110K Miles on it, no noises or issues, runs well, no warning lights.

Appreciate any insight you can provide.

 

Sounds like two things; first, leaning out (not enough fuel injected or a vacuum leak) second; restricted exhaust (cat converter and/or physical damage to the system). I probably would clean the MAF sensor and throttle body while treating the fuel with a cleaner. Also have somebody sit in it and goose the throttle while you observe the exhaust to see if it is blowing a good amount of air and not 'wheezing'. That's just for starters, but they are inexpensive things to do.
There are special cleaner sprays for the MAF and throttle body so make sure you use them.

 

Could be low fuel pressure. If the pump can't deliver enough fuel to handle WOT the mixture will go lean. Does an empty or full tank make it act any different?

 

That's right, and I came back to mention fuel filter and fuel pump driver module although the FPDM usually acts up by just cutting off the fuel pump, not restricting flow. In fact, if the fuel filter is old, just replace it anyway.

 

Spark plugs are worn out. It doesnt set a code because the misfire monitor is only active below 2500 rpm. Motorcraft plugs and new coil boots should fix you up.

 

I am beginning to think the same thing. Plugs may just be worn.

I checked the TPS today, functioning properly, checked air intake as well. I am going to clean the TB and pull the plugs.

I read may times it is the catalytic converters but, it's not like there is any more flow or pressure when I punch the pedal, when hot it will just stumble and not even try to climb to even think the cats are clogged. When it was cold, I floored it and took it to 90 with no problem. When it starts to fire it revs high which I would think if the cats were clogged it would have a hard time at higher RPMs.

It does this under load and while in park. When I stomp the pedal, it doesn't even get a chance to rev up for the exhaust to be restricted. Still a possibility though, I've seen stranger things.

Thank you all, appreciate the input.

 

The guy's got it wrong...a plugged converter will act like a horsepower limiter, get to a certain load and the engine just won't accelerate any more. So it's not that.

With 106,000 miles I am pretty certain it's ignition. Your plugs need to be replaced, along with the boots and possibly the coils. Replace the plugs and boots first. Go over the procedure outlined here and elsewhere about changing plugs "hospital clean". If you have the budget, replace the coils at the same time. They may be working and they may be breaking down.

When you go full throttle the chamber pressure is maxed out. It is harder to get a spark to jump (needs more voltage) and the increased voltage might find a different path to ground, like on a carbon track or through a miniscule hole in the insulation. It's a high resistance path, somewhere above the voltage required to spark at idle or mostly closed throttle, but below the voltage required to jump a spark at full throttle.

Everything else you've done is good, but the problem is ignition.

R.

 

Spark plugs that fail to fire in this situation would also result in heavy misfiring. Misfires have not been recorded as a trouble code which means they are mild or non-existent. So while spark plugs are a possibility, fuel delivery still has to be suspect.

 

Me I don't wot at anytime but you also have the fuel pressure sender on fuel rail that is vacuum assisted to anticipate this . Not that i think its the problem just fyi.Definitely a new fuel filter , just clean your cops good oems rarely fail .
Do a hosp clean plug install with sp546 . Plugs are only rated for 60k . Torque wrench in plugs 25 -28 foot pounds . Replace any connectors that don't lock on . Then we will talk about injector cleaning testing /replacement . A bad injector can kill your engine for good . How you do your plugs are important ,cleaning out cyl tip area with carb cleaner is really wise . Just using a small amount of dielectric grease on boots ends is important .Changing all the cops for aftermarket is also iffy .
None of this hurts or goes to waste .
Bad plugs can damage your pcm outputs .

 

Spark plugs that are wearing out or the boots that are failing due to voltage stress don't cause heavy misfiring all at once. They start gradually. As the gaps become wider by micrometers (used to be called microns) and the required voltage to fire goes up, different places to arc to ground start appearing. Also, as talked about on this board, Ford programming allows quite a few misfires before it lights the Check Engine Light. And if they only happen at WOT they occur few and far between, making it even more unlikely that they'll cause a code to be set.

No one ever said replace the coils with aftermarket units. The Ford coils are available for $25 apiece if you look or you could buy Densos, as Denso supplies the OEM coils. But as I wrote above, change out the plugs and boots first unless you have the budget to replace coils at the same time. Weird info: Rockauto has a core charge for Densos, the only brand that does. I wouldn't be afraid of NGK or Delphi, either, even though they are "aftermarket". I like Accel yellow but the Accel coils have exactly the same specs as the others, so I'd pass.

R.

 

Check with your dealership if your truck qualifies for 07M08 to replace faulty fuel injectors

 

I learn something everyday if I can just remember it ?
Just trying to save the guy from the wholesale cop change outs. Don't know what obd reader he is using or how . Baseline is plugs/ boots/fuel filter and go from there.
Dealers usually will just replace a faulty injector not all of them if covered , I replaced all of mine .
60k is the new plug change out interval,
I also suspect a vacuum leak or an intake runner problem ,

 

Oh, where did you read this 2500 RPMs thing?

 

Did some research and found out I was wrong about the 2500 RPM limit. The misfire monitor is active from 150 RPM to redline. There should be misfire counts in mode 6 data if it is indeed misfiring. Sorry for the wrong info I was thinking of the power balance test on Ford's IDS software and got it mixed up. Thats not accurate above 2500 RPM.