Lack of power
 

I bought my 98 986 a little over a year ago. It's a manual with only 36k miles so it's done a lot of sitting. I made a 600 mile drive home through mountains when I first picked it up. I was staying about 60 mph through the mountains and when it started going up a hill I noticed it had slowed down some, when I went to give it more throttle I noticed I had it to the floor and it was still slowing down. Now this was not a very steep hill so I knew it shouldn't have a problem. I turned off the cruise control and completely let off the gas and when I gave it gas again it had no problem going up the hill so it was just like I wasn't giving it any throttle. The car runs and sounds smooth and great. No misses or sputters. I don't have mountains where I live and never take it out of town so I've not noticed the problem again but the other day I raced my brother in his 2003 S-type 6 Cylinder 16 second 1/4 mile Jag and we were dead even. So I know my cars not running at full potential. Any suggestions?

Clutch?
Try taking off in 3rd from a stop and see if it stalls easily.

The clutch feels very solid and isn't slipping any.