Well, not an expert, but I can offer these suggestions... When was the fuel filter last changed? That should be done yearly. Same with air filter. The fuel pump should also be checked, although I think that's more in the working/not working category. Vacuum leak?
OBD II didn't enter the picture until the 1996 model year, so I'm rather certain that your car is OBD I. I don't know if OBD II incorporates I, so if you go that route be sure to check exactly what you need before shelling out money.