My car has always had a funny clutch action that just shows up radomly but it has never slipped until now. After I got the longtubes and dyno tune the clutch started slipping but only from 4,800 rpms and up. It will jump from 4,900 to 5,500 then fall back to 5,000 or just jump all the way to 6,000 when I am at wide open throttle. It will not slip down low I can be at 900 rpm in 5th and floor it and it pulls smoothly with no slipage. I took the car to ford and they said it was fine and I took it to an independant shop and the said it was fine they said it barked 2nd ard 3rd to hard for the clutch to be slipping. I have noticed that it does not slip up high unless the car is hot or the weather is very hot. Is the clutch shot or could it be something else? By the way the car is 11 months old 10,000 miles and never seen a track. I baby the damn thing. By best friend drove it and he said my clutch sucked because he could not start off smoothly at all. He has a 04 Mach 1. I am just used to having to play with the clutch to get it to start smoothly.