about 2 weeks ago i was driving about 60mph and the car started knocking and it died. At full throttle is misses...then backfires..and finally dies after it makes a knocking noise for maybe 10-20 seconds. The car drives fine as long as i dont go over about 40mph or mash the throttle. I have already replaced the throttle positioning switch. I checked the codes and it said "P031" (MAP or Manifold Absolute pressure sensor. I replaced it and it ran fine for the past 2 weeks. Last night I was driving and it died again...SAME CODE!. I replaced the MAP sensor about 20min ago and it didnt help at all this time but still comes up with the MAP sensor code. any help on this one?