Hi. I have a '93 Ford Probe GT (2.5L/V6/manual/120K miles). It hesitates and bucks occasionally, sometimes even stalling. Also, the check engine light comes on frequently. I took it to a shop, but they could not get the car to act up, nor could they determine what exactly is causing the check engine light to come on. They changed the plugs and plug wires, but the problem remains. Sometimes it hesitates/bucks when accelerating from a stop light, and sometimes it hesitates/bucks during acceleration in the 30-40-50 mph range. What do you think the problem/solution is? Thanks.