I have a 95 Firebird can you order just the opti sensor then get new cap and rotor instead of replacing with a new opti.

 

Even if you could, it's not a good idea. Since the bearing in the back is another point of wear. Stick with OEM and keep all the paper work connected with its ordering. You might as well replace the seal in the timing cover when you change it and by all means, be sure you have it installed correctly. I bet nearly 1/2 the people posting here have installed it wrong??????? If it hasn't already been done, plan on replacing the water pump too.

Take a good look at the hoses and belt while you're there. If the belt needs replacing, plan on the tensioner too. It probably won't hurt to put a bead of silicone around the lip of the cap on the opti and pile on the dielectric grease on the connector.

 

I would use only O2 sensor friendly silicone sealer.
And, I wouldn't put silicone grease anywhere near a vacuum vented (later) Opti-Spark -- it will find its way to the O2 sensors and contaminate them.

Tom Piper