Randomly while driving, occasionally while parked, the check engine light comes on,, the speedometer stops working. As well it basically seems as though it kills the engine but if I keep giving it gas the car will still stay running and driving(sputtering some) and only die completly when stopped to idle. It kicks itself on and off randomly while drivin, and it does not store codes. I tested it yesterday and drove it around the block the check engine came on and sputtered some, then it went back to normal, I got home and parked it and checked the codes and they werent stored at all. I;m not 100% sure but I do notice it happen more when the car shifts into 2nd and 3rd gear, or downshifing into those gears(automatic). I've been told Speedsensor, sensor on transmission, as well the computer. I've checked for loose wires, which seems like the most obvious answer, with it kicking on and off.. any advice ?