My car is a manual transmission car and is about 14 years old. I have recently noticed that when I am driving along in gear (ie foot is not on the clutch at all) that when I put my foot down hard on the accelerator that initially my engine revs go up fast and the acceleration then comes on more gradually with the revs seemingly coming down as the engine actually starts accelerating.
My understanding is that when in gear the engine speed should be directly related to the road speed so the engine revs should go up at the same rate as my speed. Instead it feels like my clutch is not fully engaged and it then takes a while to engage.
Is this normal or is this a sign of a problem somewhere in my car? If (as I suspect) it is a problem is it one that I should have fixed urgently or is this just something that happens to cars as they age and I can leave it to get dealt with in its annual service in six months?
Edit to add: The car is a Toyota Celica from 2003.