Oh, boy. Opti-spark is the distributor that is mounted on the front of the engine, under the water-pump. If it's factory, it's kind of a baby-sh!t brown color. It might have some water in it. Is the car stock, to your knowledge?
This might correct itself, assuming the ventilation tubes leading down to the unit are working. But my experience has been, once water gets inside, it's on it's last legs. Pull the blue elbow up out of the intake ducting (leaving the small hose attached to it, of course) , and stick your finger over it. With engine idling, feel for nice strong vacuum. If present, reinstall and let the motor dry the distributor out.
Ive always tested mine by putting a small piece of thin paper to the hose that connects to the blue elbow. If it sticks to the hose, vacuum is flowing. The blue elbow is where the vent hose gets fresh air from, and the vaccum side comes from intake. The reason for the paper is that with the vent harness restrictor valve, its hard to determine if its flowing just by feeling for vacuum.
First, make sure its connected to the opti and the intake, and if it is, its time for a new vent harness! From what i understand, the restrictor valve can become clogged, and you have to get the entire vent harness assy. to get just the valve. Like SEOK stated above, its good practice anyways, and from others experiences, the vented opti with a clogged vent harness isnt long for this world...
WOULD THIS ALSO RETARD MY TIMING THEREFORE LEADING UP TO SLIGHT PING AT TIMES WHEN IT MISFIRESPremature opti failure, as since the opti wont be able to clear the condenstation from inside without fresh air flow. It also helps keep corrosion down on the cap side, pulling the oxidation gasses created by the spark transfer from the rotor to the cap out. Opti will fail sooner, with typical opti failure symtoms (hesitation, random misfiring, hard starting and eventualy intermittent dieing, until one day it wont crank at all!)
Its possible, optis cause a PLETHORA of different problems. Give us a little more info. How old is your opti? When are you experiencing a misfire? Alot of times, detonation (pinging) can be caused by a bad EGR valve. My 95 had a misfire with pinging under heavy acceleration, but mine was a SEVERELY clogged pass. side cat. BUT if your opti vent harness is fubar'd, it needs to be replaced soon anyways.
Is it "putting" on both sides equaly? The way i finally diagnosed my clogged cat was comparing the exhaust flow between both sides. Pass. side was weak compared to the drivers side (and it stank like sulfur, pass. side manifold would glow red, and it ran faster with 1/2 throttle than it did to the floor). As far as the opti, the optical sensor can get damaged by excess condensation, and the vent harness being clogged will not help things either.