Turd Ferguson

I have a 2007 with the 5.4 with 10k miles. I had a magnaflow cat-back system put on, worked fine. I installed the 3" AF1 intake on it, and since then it's been very sluggish over 40 mph. It accelerates from a stop just fine. Symptoms :

- Once I get above 40, if I slowly get on the gas (not enough to make it shift), then the RPMs barely move up from 1200-2200 RPM. Give it a little more gas then it struggles a little, shifts, and the RPMS jump up and works fine.
- If I'm above 40, and try very slowly accelerate at 2000 RPM, itll stay there for a second or two but then drop back down to 1200 RPM
- If I get on the gas quickly enough to make it shift and I'm above 2200 RPM, then it works as expected.


I took it to the dealer and asked them to look at it while they did the oil change, tire rotation, etc. They said they didn't see any problem with how ti ran, which is BS seeing as how it does this consistently. Anyone have any ideas?

Good old Bill

Unfortunately, I agree with what is going on. Fords have never been, in my mind, aggressive enough to down shift on demand. GM's do, spit-spit, can't believe what I just said. Maybe, someone will give up good info. Good luck.

rplatt56

Tranny clutch is holding it back while slow acceleration. You are putting more air into the system and may need to get on it a little more. Question-- did you disconnect the negative battery cable after your CAI install? If not, try that to reset computer.

Turd Ferguson

Yeah, I did disconnect the battery when I did that. I'm going to stop at my parents house next week when I'm on ym work trip and take my Dad's 2006 XLT out and see if his does it too.

rplatt56

i think what you are experiencing is the OD clutch kicking in. Mine does it if i give it light pedal. So i just sorta get on it until i get up to around 65. then my rpms drop to about 1400

Turd Ferguson

That actually sounds like it makes sense. I'll post up next week if it turns out I'm full of crap