I was very frustrated trying yo find a solution to this idle problem. It would surge and kill. When driving about 40 mph and then accelerating the car would lag and stall until pedal pressure was let up. A friend suggested I check the coil pack. I put in new wires and plugs and the problem let up a bit. When I put a good used coil pack in, the problem went away. From what I could tell the coil pack was the main issue.