I am considering buying a 1984 380 SE from a friend who is, frankly, tired of it. The body is near perfect and the interior needs a bit of work, but isn't bad for its age.

When it is cranked, it starts quickly and idles high (about 1,100 RPM) but smooth, and when it has warmed up it revs smoothly. When I try to drive it, however, it will only accelerate with a very slight pressure on the pedal -- maybe half an inch of travel. Any more pressure will cause the vacuum gauge to spike (i.e. lose vacuum) and the power to drop off quickly. A slight uphill grade is very difficult to climb, and on flat ground it still accelerates slowly.

I have been told that defective fuel pumps and dirty filters can cause this, but a mechanic warned me that the problem might be in the injection system, which can be very expensive. My basic question is, given what I've said about the car, whether I should bother with this car, or is it worth putting some money into?