i have a 90 lx sport, and the scanner will not comunicate with the computer on the car. i have tried different scanners and the same thing happened. do yall know of any common problems that could cause this to happen. the car runs good but i am only getting around 10 to 14mpg. i am guessing that it is an o2 sensor or the egr, but i would like to be able to read the codes to make sure before i just start spending money. if anybody knows any problems or have experienced this any help would be greatly appreicated.