I have noticed an increased amount of black carbon build up on my exaust tip. This is my first subaru, and i have had it about 4 months. I have a really short commute so i only put 2K miles on it so far.

Anyway. i am wondering if this build up is an indication of needing a tune up.

My 2000 out back sport is non turbo, and to be honest it is pretty slow. a little weaker then i had expected. It is slow off the line, and hesitates if i give it heavy gas already at speed.

 

So here are my thoughts. Is the carbon causing performance problems because i put so few miles on my car at any time, so it never gets really hot enough to burn it off?

Maybe i just need new plugs? (it has 50K on it so probably still original)

If i change plugs should i also change wires?

I already did air, oil anf fuel filters. not much affect.

Modern day engine computers learn the driving style inputs of daily driving, and tune the car's systems accordingly. Many garages will tune up a car and then test drive it thrashing the daylights out of it for ten minutes or so. This reteaches the computer new performance demands. Then when the customer picks up the car, barely touches the accelerator and is shot back into the seat, they are convinced that they got their monies worth. Your short commute maybe have lulled your gem into complacency. Take her out onto the highway, give her the gears (using common sense of course) and clean the carbon out of her. Whether you have a manual or automatic, drop her down a gear from where you normally would drive at that speed, and watch your tach so that you don't overrev and hurt something. Ten miles or of hard performance driving may clear up your concerns. If it doesn't, then its time for a technician to have a look and pull some codes. Hope this works for you. Good luck!