Did the garage use a diagnostic code reader to find the problem or did they just go ahead and replace the items in the hope it would fix the problem??
As to the speedo, the sensor on the gearbox either works or it does'nt it would'nt suddenly start over-reading
The engine fault light normally is an indication of a sensor or valve failing, get the garage to either show or tell you what fault codes are registered in the ecu, they will be a P followed by four numbers eg P0150 which means "lambda sensor 1" at fault, then if the fault continues post a new question with these recorded fault codes for further diagnosis
nigel
February 2010