I have to say
sell it. I love my 99s I have two and have sold three. The thing about 1999 986s is that unless you have some special attachment to that
particular car, they are (for now) easily replaceable. The one you have has a lot of miles and needs some work. If you miss it after it's gone, you can very likely find another in similar, or better condition -in the right place, at the right time. Keep the memories, let someone else have the car.
Oh and
post a picture. 