nasbc

93 civi dx hatchback with auto trans speedo doesnt work but sometimes while crusing will run irraticly jumping from 0 to 120 mph and the odometer doesnt work either. i have tested the vss and seems to be within specs wiring seems to be good and connections seem tight is this a issue that happens often with these cars iv heard it could be a cluster problem what you guys think and if it is a cluster is there a way 2 test it and also do you know who could repair or shoudl buy new or used?