Truck is an 04 screw 5.4 w/ 166,000. First started to notice this about 3 weeks ago but became even worse after i changed the cam phasers and timming tensioners and chains. When driving and lightly pressing the accelerator (maintaining speed highway or around town) the truck will start to bog, droning exhaust noise not maintain power. If I let off and give it throttle again it will kick in and go. This happens even from a stop sometimes, but if i just get on it it will go fine.

Not throwing any codes, within the last 6 moths I have changed the spark plugs, coil packs, fuel filter, cleaned the maf ,throttle body and transmission fluid.

I have searched this and a couple other forums and found people with the exact same symptoms but they never responded back to thier thread with what the fix was.

A few months ago I cleaned the throttle body and this fixed the clunking or jumping of the truck under light acceleration at highway speeds. Wondering if I have a throttle body problem or something else. Don't understand why it got so much worse after doing the phasers etc. Timming seems fine as it runs great when i get on it.

Anyone else run into this before?

Thanks

 

Yes, the exact thing has happened to me...and I have yet to fix it, find a fix or anything and it doesn't hesitate while it's cold, but once it's up to normal operating temp for about 20-30 min, it starts it's shenanigans

Here's the list of parts I've changed/cleaned/updated/etc:

1. Cam Phasers
2. Tensioners
3. Trans (lost O/D) not related but hoped that it would've helped
4. Computer Updated
5. Fuel Pump Module
6. Plugs
7. COPs
8. All fluids flushed
9. Throttle body cleaned and changed
10. Fuel System cleaned-Injectors individually tested- Ops Chk Good
11. MAF cleaned and then changed
Ummmm...I think that's it...

Here's a link to my thread started a while back -

https://www.f150forum.com/f4/hesitat...og-down-86642/


If you come across any ideas, hints, tricks, etc...let me know!

I have recently picked and an Edge programmer and on the canned Trans Tune, the problem is about 95% solved. The truck still does it but it's barely noticeable to other passengers, but I still notice because it drives me nuts!

 

Thanks Ian, I read the entire thread and it seems several people have the same issue but none have truely resolved it. Towards the end of the thread you replaced the fpdm and seemed to think that was it. Now i am guessing your still having issues. Did you replace the fpdm yourself? Did you notice if it had the corrosion it is noted for? I am going to drop the spare tire and insptect it tomorrow.

 

I did not change it myself, I had it done while the trans was being rebuilt. But he did give me the old one and there was a bit of corrosion on but nothing that I thought cause a problem.

I am convinced now that it has something to do with installation of the new cam phasers/tensioners. Again, I did not do those myself, the dealership did and I brought it back on afterwards with the problem and they kept telling me to "give it time, the truck is relearning itself.." it's being about 5-6k since that was done...

 

An update: It appears my "new" coil packs that I installed a few months ago are the problem. I got these as from ebay, the $99 set that has gotten good reviews of the forums. After I read post #7 in this thread http://www.f150online.com/forums/199...e-applied.html It got me to rethinking my coils. I saved the original coils and decided to replace them back in two at a time. This moring I swapped out 2 and drove to work. Problem still there. I swapped out the next 2 and drove home. Wow!! problem 95% gone. I managed to slightly duplicate it one time but for all intensive purposes it is gone. I am going to swap out the rest tomorrow. I think new chains etc. magnified this problem as there is a little more "tension" on the motor and the failing pack or packs wen't responding as well on light throttle (read that guys post). Ian , you may want to check your coils pack or get them load tested, even if new.

Hope this isn't one of those posts where i am back in a couple days and say nevermind. Don't think so as the difference was just to dramatic.

 

Man I wish that was the issue. I had the problem after the cam phasers and tensioners and plugs. I changed the COPs later and the problem is still there. Once I get home again, I'll pick up another set and see if it changes...I'm open to any ideas now. Thanks for the update!!!

 

My truck is doing the EXACT same thing. It stumbles under light acceleration once up to operating temp. Ford must no something about this? I bought the truck yesterday and purchased a Base Care warranty so I will be watching this thread closely with suggestions for the dealer.

 

Still sound like it could be a misfire.

Have you guys checked the coolant temp sensor reading on a scanner when up to operation temp?

if the phasers are done and the timing is correct, it sould not be the problem. Wont hurt to check the cam timing on the computer too.

 

my 07 screw doess it and so does my E250 work van...hoping somebody finds a cure

 

my 07 only has 44k