Hello my name is Jake and im new to this site. Im asking for a little help with my problem. I have a 2004 F150 Fx4 5.4L that i got a few days ago. I notice the truck stumbles and falls on its face at WOT or under a load. I pulled the codes and found P0451 and P2105 so i went throygh the steps of cleaning the MAF and throttle body, while in there i notice that the throttle body, elctronic throttle and TPS are all brand new. Clear the codes and the problem still exists. Throws another code and this time it is P2006 so i pull the intake and the intake runner seems to be working fine with no broken rods or clips. Not sure if i should have done this part but was adviced that i could remove the blades from the intake runners, so i did. Put it back together and it has a hell of a lot more power but still misses. Now ANOTHER code come up this time its only P0451. Ive tried checking all the coils and there good. Can anyone please give me some tips, im beyond lost. Thanks for the help!

 

My old civic used to choke and stumble at WOT. My issue ended up being bad plugs. How many miles are ya at and do you know if the plugs have ever been changed?

 

They look to be original, thats my next plan of action. The truck has 89,000

 

I would definitely do a plug change! I think ford released the original plugs should be changed at 50 or 75k miles...can't remember.

 

Theres no way i could get that lucky lol i pulled one plug and it didnt look bad at all so i decided to move on.

 

Changing the plugs right now and of course the back 2 on both sides broke.....fun..fun

 

Update... got all the plugs changed out and of course while doing the job the battery was disconnected which cleared the codes. Test drove the truck and it ran perfect...then all the sudden it fell on its face again. Shortly after it threw the code P2006 intake runner stuck closed. If the cmcv actuator was bad could it cause the truck to go into limp mode?

 

I had the same symptoms you are describing on my previous truck('05 FX4 5.4l) brought it to the dealer to find out what was wrong and come to find out it had 4 bad injectors. Ford put out a nationwide warranty replacement on the injectors instead of doing a recall because some are good and some are not. They put a mileage and year limit on the warranty, 11 years/125,000 miles if I remember correctly. Oh and the truck did not throw a CEL. I cleaned the MAF, did plugs, and my brother inlaw is a mechanic and ran some stuff through the motor that cleans out any carbon build up all with no luck. Had the injectors replaced under Fords dime and truck ran wonderful after that.

 

Check your FPDM ( fuel pump delivery module) its on the crossmember behind spare tire. It corrodes and can cause weird issues too.

 

Never saw it give a P02006 Code though...it's worth a look. It was sounding like a clogged cat to me..