Hi all. I would like anyone's opinion about my truck. It is a 2004 F150 Lariat 5.4. I just completed Cam Phaser and Timing Kit change. My problem is that when the truck is cold it runs smooth on acceleration. But, once warm it bogs down. There is no CEL on. It happens when I press the gas. It accelerates but, then bogs down as if loosing power. I am going to change the spark plugs and vct's just to eliminate these as possibilities.
What are your opinions?

 

Had similar problem with my 2007 f-150 4.6liter Supercab, changed plugs, and coils, same issue, then changed out the fuel filter, finding black coffee coming out of the output end of the filter. After replacing filter my truck ran like new.
Hope this helps!

 

I had fhe same problem but change the fuel filter and took apart the air filter tubbing. I cleaned it and used a carburetor cleaner to clean the throttle body thru the inside. lots of carbon build-up. havent had a problem since then, 3 yrs ago. hope this helps.

 

Hey guys thanks for the advice. I definitely will change out the fuel filter. Never even thought of that. I will let you know how I make out. Thanks again.

 

also check the condition of your FPDM while your under the truck changing the fuel filter.

 

Just an update. I checked the fuel pump driver module. Looks like someone had placed some grease between the back of the module and frame. Other than that everything looks good. Going to change out fuel filter and let everyone know how I make out.

 

Read this, then go outside and fix your truck, takes about 15 min and I will almost guarantee it solves the problem

https://www.f150forum.com/f4/bog-dow...solved-166431/

 

^ X2

 

Hey guys. Believe it or not I did read this thread about three weeks ago. My original foam was completely gone. So I replaced it, but I think I should examine it more closely to make sure the foam I did put on is sealing properly.
Thanks again for the advice. Very much appreciated. Regards...Spike

 

Hi all just an update. I thoroughly cleaned my throttle body, especially around the butterfly plate. Man it was solid black. Used tb cleaner and kepted spraying till all the carbon was gone. Buttoned things back up and she does not hesitate at all.
Many thanks to all that gave helpful suggestions and tips. You guys are the best.
Cheers Spike