An old 91 no longer will give out codes. When I first got it the check engine light appeared but I was able to flash codes and the tach worked. Now codes no longer flash, the tach does not work but the car stills runs, though not well. I tried the Innova diagnostic scanner last night and it did not connect. I figure either the computer or ignition control module is gone, but with the car still running am not sure which to get. I do know that the car is supposed to run in "default" mode if all else fails. Any help would be appreciated, this car is for a college bound kid to use.