nahaloth

Greetings, all. First, I'd like to apologize if there is another thread with the answer for this. The search feature couldn't find anything that matched what I am experiencing.


I own a 2006 5.4 Triton 4x4 with about 145k on it. No mods besides a K&N filter which is coming out TODAY. Truck has had the PCM reflash applied.


Here is the problem: If I am gentle with the throttle coming away from a red light, the engine runs fine. Plenty of torque, kicks me back in the seat a bit. But if I go WOT at any point, the engine feels like its running lean between 3000 and 4800 RPM. Bad enough that it loses about half its power. I tend to drive like an old man, but when I need the power, it isn't there any more. Truck has also started towing like a turd (I commonly pull a 6x12 cargo trailer that weighs about 2900 lbs, WELL within limits. Had no problems with it up until this power loss issue). I have no power up hills, no passing ability, no take-off at all at WOT. If I baby the throttle it gets a little better, but I still feel the power lurching, as though the fuel isn't right, until about 4800 rpm, at which point the truck takes off like a scalded dog.


A list of all preventive and remedial maintenance done thus far:


- RELIGIOUS oil changes with 5w20 full synthetic, run Seafoam in every other change to fight the gunk. I do this to try to keep the galley clean and save my VCT solenoids and phasers. Only run Motorcraft filters.
- Spark plugs changed at 98k (Motorcraft plugs)
- Transmission fluid/filters changed at 86k by dealer, then again by me last night at 145k.
- Cam solenoids replaced at 90k due to annoying rattling sound. Made the sound go away for a bit, but it came back. I pull the solenoids every so often and clean them. They have never been too nasty in the past, but for some reason the act of pulling them and cleaning them quiets the phasers down for a few weeks.
- Cleaned MAF sensor a few days ago.
- Changed fuel filter the same day I cleaned the MAF
- Replaced FPDM approx. 6 months ago when it corroded in half and burned to a crisp. Nicely done, moron who put is OUTSIDE in the rain...


Things I know are wrong:
- Cam phaser rattles like a paint can until I stand in the throttle for a few seconds and force oil up the galley. Sound tends to quiet down once the engine warms up and I drive it for a while.
- AC condenser has the infamous clog in the metering orifice, makes me want to strangle the idiot who decided to do away with a standard quench valve.
- Power falls off in the mid range, as posted above.
- Gutless 4 speed transmission on 3.73 gears (personal peeve; not sure how Ford can call it a "tow package" when they put passenger car driveline components in a truck meant to haul 10,000 pounds. This thing needs a 5 speed or some taller gears).


Now that you have suffered through this long post, do any of you know what could be causing this? I think the K&N filter might be causing some of it, but it's been in there for 5 months and the truck just now started having the issue a few days ago. I am getting no codes, no CEL. Just a severe power loss at WOT between 3000 and 4800 RPM. No misfiring or bucking. Engine sounds and feels smooth until I hit the range above, where it starts to lurch. I can feel the power increasing in seemingly incremental steps as I approach 4800 RPM, where it seems to max out again.


Any thoughts?

j.low

You might check your catalytic converter (s). They can cause weird problems on hi mileage trucks.

tiresmoke

>>Cleaned MAF sensor a few days ago.<<

MAF sensors are easily damaged. IF this is the case, it may be OK at low throttle but at open throttle & high air flow, it may not be reading properly.

nahaloth

I took care of it. Bought a 97 F350 PSD with Centaurus II trim package. No more towing problems. And it gets better MPG. Go figure. Nobody builds a gasser with real towing longevity any more. VERY disappointed with the F150/5.4. I'll never buy another one.