Ignition Control Module, Distributor Cap, Change the Plugs, Air filter, Fuel Filter, idle Control Motor, Vacuum Lines. Any one of those or a combination.
The ignition control module, distributor cap, and spark plugs are my first thought, shouldnt be more than $200 if you pay a mechanic to do it, half if you DIY. After that check the air and fuel filter which probably need replacing anyway, and I vaugley remember a weird shaped vac line going around the back of the engine that most mechanics would have replaced with a foot of regular vac line instead of the curves piece from the manufacturer, which causes it to rub instead of curving around a bracket.
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