I have a 96 z28 and it misfires and I cant find out why.
The plugs have about 3000 miles on them
I changed the wires
I changed the distributor cap

It still misfires, I have scaned the codes several times and I have gotten random misfire, and cylinder #4 misfire.

I also want to know how does this engine adjust its timing if needed, I know how the optispark works but what if that optical disc is off a degree or two.

 

There are no provision for timing adjustment. The timing is controlled mostly by what the PCM sees from the Knock Sensor. Changing distributor cap on an Optispark is usually a waste of time, asit is the internal electronics in the Opti that usually go bad. Random misfire means that there is a common cause for the misfire. In the LT1 the common cause is usually a bad fuel mixture, bad coil, bad coil control module, or a bad opti. You may want to look at the fuel pressure first & see if it meets specs, and then start changing out the cheapest parts first. A solid misfire on a single cylinder is either an ignition problem with that cylinder, or a bad injector, and hopefully not mechanical damage such as damaged piston or valve.

 

I changed the coil and the car seems to run better, but still misfires. I havent checked to see if it is random or specific since i put in the new coil. I had the ignition moduel tested and the tester told me that the moduel was crap. I put a new one in and it made no difference, but that was before I changed the coil.

 

My dad is convinced that I fouled out the plugs and that is why it is misfireing. He thinks that the new coil may have just had enough power to clear out some of the plugs and that is why it is running better but still not good. Tomorrow I plan to pull a few plugs and check, as well as go back and try out the new ignition moduel

 

I had a similar problem on my '97 where I was throwing "random misfire" codes. After checking the plugs, wires, etc. I got frustrated and took it in to a mechanic. Turns out my water pump had cracked, and the water was leaking onto my distributor, thus shorting it out. I had to replace both parts, which I found for pretty cheap luckily. Anyways, hope you don't have the same problem.