Hey guys, I'm looking for some guidance! I have an 06 F150 FX4 CC w/ the 5.4. I bought the truck used about 2.5 yrs ago w/ 70K miles on it. It now has just over 96K miles on it. I've never had an issue w/ the truck until two days ago.

The trucks seems to run fine except for when it shifts into O/D and only if I'm feathering (gradually increasing) the accelerator. At this point, the truck starts vibrating and engine fluttering badly (usually around 45 mph). If I gun it at this point, everything seems to line back out and run smooth again. The truck has an Edge programer that was already installed from the previous owner (almost didn't buy the truck because of this). Those things make me nervous! I don't drive the truck on anything but the stock setting. I just keep the programer hooked up to monitor different parameters and it looks kinda cool at night.
At first, I thought it was a transmission issue developing. Well, I was playing w/ the parameters on the way home from work this evening and noticed a few things. When the truck is acting up, the FRP (Fuel Rail Pressure?) and LP (Line Pressure?) remain constant whether truck is acting up or not. However, when it starts acting up the Spark Advance drops from 36-34 down to 4- -2. As soon as I let off the throttle or gun it, everything returns to normal. If I disengage the O/D, it seems to run fine. I'm leaning towards an ignition problem or spark plug issue now but I really have no idea?
Has anyone else experienced these symptoms? Any help or guidance I can get would be greatly appreciated!

 

Having the same exact problem with mine. Seems to me to be a misfire, im thinking its plugs. im trying to figure out what the problem is too. i have an 07 f150 5.4 with 68,000 miles and a flashpaq programmer

 

You both are getting low grade misfires. Time for new spark plugs and *maybe* coils.

 

I had the exact same issue with mine before and after my engine rebuild + new COPS, new plugs, new injectors. I decided to get an EDGE to monitor things and found out the first time I tried to program the truck that it had been programmed previously. EDGE gave me the stock program and after putting it back to stock the issue was still there, after changing to the performance tune it's gone. Looking at many other threads I found out that according to the dealer this is normal when the TC lockup is engaging and disengaging. I'm not sure why some experience this more than others but in most case the Ford shops said it's normal. Either way I would also try the performance tune on the edge after you change your COPS and plugs. It worked for mine after new COPS and plugs didn't fix the problem.

 

Change the plugs.

 

Same issues here.
A bunch of posts about it in the Transmission section.
https://www.f150online.com/forums/tr...-problems.html

GLC chimed in there too and I think I need to start by changing the plugs.

 

Thanks for the responses guys! My check engine light came on momentarily this evening. Don't remember exactly what the code ID was but according to the programmer it's a cylinder 3 misfire. Looks like plugs in my future.

 

In a previous post (8/4/11)I discussed the random missing of my 2000 5.4 L engine. I only have 46,000 miles on it but park it outside all the time in warm, humid Miami. The miss was random, but much more prevalent just after shifting into 4th (Auto Trans)from 40 – 50 MPH. The check engine light never came on. I checked out the fuel and fuel filter and that was not the problem. I looked at all the similar posts on the internet and found a few leads. I checked and my hood seal and it does leak a little right where the last two COP’s on the pass side are located. I pulled these 2 COP’s and they looked good, but the screw holding them in was corroded, especially on #3. I cleaned up the screws and put the COP’s back in and all missing has ceased! On one post I saw where this was done and it also worked with me. Apparently it was a simple grounding problem!! Hope this will help you.

 

My 02 F-150 had the same symtom. I just replaced all 8 of the coil packs and it fixed the problem. I used the Accel Super Coil packs.

 

Good luck with those !! Accel COP's don't have a very good reputation around here....