by 'dumping the car', do you mean selling or scrapping?
Really sounds like it wouldn't take much work or money to straighten out the idle issue. At 200,000km, the engine still has life. The body, that can be a whole other story...
Have you checked the intake hose for cracks? Have you checked transmission fluid?
93 mx3 gs: atx-mtx swap, 94+ spindles
94 mx3 rs: new engine, running again!
88 jeep cherokee: 4.0, 4wd, the 'glitchy ride'.
87 rx7, new and needing lots of love!