when people say the optispark is bad does that mean the whole unit or the cap and rotor???? my car is missing when it warms up and spark knocks and idles rough, most people seem to think its the optispark unit. My question is do I have to replace the whole unit or can I just replace the cap, rotor etc... also do I have to remove the unit to replace the cap and rotor. I am new to this lt1 bull crap. Thanks for the help.....

 

Do yourself a favor and type opti in the search box? You will find TONs of threads with the Opti info. Read as many as you can, and if you do decide to replace the Opti, do NOT just replace the cap & rotor, LT1's just don't seem to like used/refurbished/cap&rotor only Opti's, they seem to do very will with BRAND NEW Opti's.
And, since you're replacing the Opti, get a NEW waterpump while you're at it. Waterpumps going bad is the biggest reason why Opti's get f'd up.
Good luck.