Timing on my Del Sol is +5

My 93 del sol failed smog +5 and i was wondering how do i set my timing back down because to my knowledge the timing is pre set by the computer?

When was the last tune up?
Was the car @ normal operating temp when you had the test done?

Suggest -

New plugs
Air filter
Air Temp sensor
Clean throttle body
PCV valve
New O2 sensor

The timing can be adjusted with a ttiming light and by loosening and adjusting the distributor position. There are marks on the crank pulley that line up with a pointer on the timing cover to allow you to set the timing properly. The car must have a jumper installed in the diagnostic plug near the ecu in the passenger footwell, it should be a blue 2 prong plug. The Check Engine Light will remain illuminated during this process, and the vehicle's timing will be locked in place, so that it doesnt move due to correction from the ECU. Hooking up the timing light and pointing it at the crank pulley you should see 1 line by itself, and 3 grouped closely together. You need to rock the distributor until the pointer aligns with the middle of the 3 marks. Tighten down the dizzy, remove the jumper and your done!