Christiancito

Hi guys, I have an 07 5.4 that when cold runs good but as soon the temperature needle reaches normal running temp the truck starts running like crap. It loses power considerably, it will reach top speeds (70/80+Mph) but you kinda have to floor it to get there. Previous owner said that had the cam phasers replaced and so far I've replaced the following: Spark plugs (motorcraft), coil packs, knock sensors, whole intake manifold and oil change at the dealership. I just don't know what else to do, just purchased the truck month and a half ago and already have so much money into it that's not funny. Don't think I can spend more money in this truck, it's driving me nuts. Any ideas what could be causing this problem? Thanks for your help!

nyles68

Clean the throttle body if you haven't already. Make sure the cleaner is spec'd as safe for Teflon coatings. Confirm the foam on the air filter is good. Make sure to use an oem filter. I used a K&N and it wasn't sealing properly. Also do a throttle body reset. Search through the forums and you'll find that procedure. It's the one that involves turning the key, slowly pressing the gas pedal to the floor and quickly releasing. Also make sure all plugs are torqued down properly (33ft-lb). If you're hearing a ticking sound it could be associated with a lose plug. Mine had the same issues and completing the above checks resolved all my issues. A bit of a pain but these are fairly inexpensive checks you can do yourself before you get into the more expensive options.

Christiancito

Now that you mention it, there is a ticking sound that started after the intake manifold was replaced but i was told it was a sticky lifter, might be a spark plug uh? I was told not to tighten them up too much but not im going to torque
them to specs. Thanks! I will see of that helps!

ColdinCanada

Easy things first, engines need fuel, spark and air. A reduction in any of these will hamper performance. Nyles has some great tips. I would add (if I didn't miss it) fuel filter and FPDM under your spare tire. If this is a new vehicle to you the FDPM should be inspected by you anyway. I'm assuming your fuel tank has been filled with quality fuel recently. Im certainly no expert but one other thing I can think of is the VCT solenoids as I know they begin operation at a certain engine temperature. Again, full disclosure, my knowledge on this is weak at best. Sorry I can't be of more help.
Dev

Christiancito

Ups... I used crappy gas last time I filed it up, like, from a junk yard crappy... :s
Tank is almost empty and will fill it up with good quality gas. Ive had this truck for a little over a month, so this is a new vehicle to me. Will check fuel filter and FDPM (whatever that is lol). VCT sounds logical too cuz it starts running like crap ONLY after its warmed up, when cold, it runs good. Thanks for your input! 👍

GhostriderI

Fuel Pump Driver Module Here is a link to a thread

https://www.f150forum.com/f4/fdpm-247020/

Krack499

iTrader: (1)

Your junk yard fuel could definitely be causing problems depending on how long its been sitting why'd you use it anyway another thing could be clogged/bad catalytic converters

muddyford911

iTrader: (1)

You said when your temp needle reaches max. Did you mean normal, or is it overheating as well?

Christiancito

I meant normal, not overheating at all. At least the gauge doesn't show it

Christiancito

I used it cuz im dumb man... Never again... Catalytic might be another cuase, sounds about right, that might explain why it losses power only when warm