My gauge is pegged always. I have a 68 327 in car. I am curious I where to start for fixing it. I don't know how to check for electrical status so I would just like to start replacing the most obvious, comman sources of this problem. So what I need help with, is what should I replace first, second, ect. And where are these things on my 68 block??

Oil pressure sender will either be on the china wall (top of intake back) just to driver side of the distributor, or it will be on driver side block just above the oil filter - on 1985 car I'm guessing china wall - probably the connector is disconnected and grounding on something - it's a single wire, single female spade connector - the sender is about as round as a Red Bull can, about 4 inches long.

So I replaced sender. Now it will at least drop to zero when I turn on key but then jumps all the way up. It has one wire going into it but it comes out of a plug with two wires. One of the wires was in my either ecm harness or fuel pump harness both of which are removed, so is something need to be re wired? Also when I tuen key it will stop gauge where its at. So I think guage works

So the wire from the plug I cut was a green one. Would that have anything to do with gauge reading??