Your temp gauge fluctuating like that makes me think it has a bad connection somewhere. Have you broken down the wire loom and traced the wires ALL the way back to the pcm? When you start the car, does your temp gauge go all the way up and back down like the others? Have you checked the wiring that goes to the cluster? I would start with that. As far as rpm fluctuation, have you checked for any vacuum leaks? The elbows that stocker is talking about are the plastic 90* elbows that are on the left side of the engine. There are 2, one is hidden behind/below the tensioner pulley.
