Abrick

Hi! Please help! My mechanic is baffled. He said he has never seen anything like it. I own a 1994 Protege. Problem: "Hiccups" Mechanic has changed out computer, filters and just about everything else. When idling, the power "switches on and off". The riding down the rode is may stall or just lose power. And, heaven forbid that you must stop at a traffic light!! You have to double clutch and even then hope it doesn't stall? Any ideas on what the problem may be. We bought it a year ago and the problem has gotten so bad, it's undriveable! miles 135,000
Thanks!!