Mitsubishi Repair: mtsubishi magna wagon surging problem, new distributor cap, magna wagon

Question
i have a mitsubishi magna wagon 92 model.  having alot of problems with surging especially underload. have replaced spark plugs, leads and also has new distributor cap.....my husband adjusted the timing which has made it a bit better but still has problem. would you have any idea what the problem could be.

Answer
Karen: Hello. You got a AutoZone close by? As I think you should have your car coded to rule out any sensor or computer problem. AutoZone will code your car for free. Or else it could be a vaccum leak. When you did the distributor cap; you did the rotor too, right? Hope this helps and good luck!