The two grounds on the bottom of the intake manifold near the firewall are the ecu grounds. ALSO check coil ground. If they are corroded or broken the ecu will not function right and will give the same symptoms you describe..
The cps wires tend to break right where the wire is terminated inside the connector. They can be re pinned but the connector is usually flaking apart by now (hence the connector swap). The wiring can be damaged anywhere around there. If you are in doubt of the connector and just want to get the car running, you can just cut the connector off completely and crimp or solder the wires together.
You said it "fires on a few cylinders" this would indicate (to me) that the computer has no idea what position the crank is in. It would have a 1 in 6 chance of getting it right without the cps signal.
I know this may sound silly but have you checked the ecu fuse? Have you checked to see if there are any stored codes?
This is the connector I like to use for lotsa stuff.
http://www.jegs.com/i/JEGS-Performan...ductId=1354645