1996 Holden Statesman After Driving Couple Minutes Engine Fault Comes On Speedo

After driving for a couple of minutes the engine fault like comes on, then the speedo cuts out and i lose 1st gear (Auto). FInally if i get stuck at lights the car will just die without warning. IVe had some sensor on the trans changed as well as the coil pack but it is still doing it. MY friend hooked the car onto the computer put no faults were present.

Any ideas???