Hey guys, I drive a 2008 4x4 with the 5.4l and 3.73 gears. I have a couple issue that im not sure whether they are related or not but both make me a little worried.
1. When driving around town and letting off the gas in traffic or for a light and then gently giving it gas again, even just a tiny bit to keep my momentum, (around 30mph) it almost seems as though the transmission is slipping or getting caught between gears because the truck will rev up to about 2500 like its in neutral and then it will catch the gear and go.
2. Also around the same speed when under light acceleration the truck seems to spit and sputter and just does not accelerate smoothly at all.

Anyone have any ideas or have the same issues? I really hope it is not my transmission going. I run an edge chip on level 2 and am a little worried that if the tranny does go the dealer will say screw you because im sure even with the chip out they can likely tell it was in there before with todays computers. (I am in Canada so i do not think the Magnuson-Moss warranty act will help me)

Thanks

 

First thing to do is return your tuning to stock and see what it does.

 

I have a 2008 XLT 4X4 with the 5.4L engine and 3.55 gears and am experiencing the exact same problems. I have never had a chip in my truck.
I noticed problem #1 when I first bought the truck. Problem #2 started yesterday and mine occurs between 45-55 mph under normal driving. I have less than 20K miles on the truck. I will be headed to the dealer soon. Anyone have an idea what is causing our problems?

 

The first sounds like the torque converter unlocking and I woudl call it normal.

The second could be torque converter shudder or an engine missfire caused by a bad COP or an EGR issue.

Have you changed the transmission fluid lately?

Darrin

 

Sorry Ford Rules, I don't mean to steal your thread. My truck had to be towed to the dealer this morning! I was driving in to work doing about 45-50 mph and it just died, no power steering or power brakes. Luckily, there was no traffic and I was able to turn off onto a side street. The check engine light did come on at this point. It would not restart.
After reading more yesterday after my last post, problem #2 was starting to sound more like a bad COP.
To make matters worse, my phone was on low battery last night so I plugged it in to recharge overnight. Guess what... I went off and forgot my phone this morning. I had a nice 2 mile hike back home in the dark on a shoulderless road. I thought I was going to end up like a dead deer in the ditch.

Ford Rules... you may want to have your truck looked at soon so you aren't stranded on the side of the road too.

I'll keep you posted once I find out what was wrong with mine.

 

Hey no problem you arent stealing the thread, the more information the better. Sure hope my truck doesnt die on me. Let us know what they determine the cause is. Hopefully i can get mine all straightened out before it leaves me stranded too.

 

I got the truck back this evening. They said the coil on cylinder #5 went bad which resulted in a fuse blowing that shut down the whole truck. They said this was causing both problems 1 and 2 above. I don't know if I believe this was the culprit for problem 1. I am going to keep a close eye on it. The service guy said it is extremely rare for a bad coil to blow a fuse, but it does happen. Oh well, I'm just glad it wasn't something worse. Luckily it was all covered under warranty.
Can someone tell me... If the coil goes bad should they all be replaced or should the plugs be replaced at the same time. All the dealer did was replace the one coil assembly and the blown fuse.