94 model service engine light

today my beast of a pontiac service engine light came on. ever since its been starting hard and doing goofy things like: the speedometer is on again off again, it seems to be making an excessive howl. and its idling very high i was wondering what pins to jump to get a code or if anyone knows what to problem might be

not sure if you can jump pins on a 94...it will need a scan tool to read it..and a 94 bonnie like mine has the obd2 connector but had the obd1 codes..it was the year gm was changing over..so it is tuff for places like autozone to read our cars..!

Thanx for the info it turned out to me the engine computer