Sorry if this comes across a little 'noob', but is this a slipping clutch?
http://www.youtube.com/watch?v=CC8YuLnT2Lw
The car is sat at 70mph, 5th gear, at 3000rpm. If I put my foot down, I get a surge in revs, but almost no acceleration. You can see when I let the gas off, the needles settle back to where it should be but this behavior is not normal.
Is this a slipping clutch? After the first part in the above video, I could smell some kind of burning.
On returning back to my local area, I struggled to get any acceleration in any gear due to this same effect. Revs up high and takes a few seconds for the car to catch up, unless I ease off the gas and let the car accelerate gently.