Decided to do the boiling water test on my "aftermarket" temp sender since I am close to having the car ready to run and drive again. Took my new OREILLY temp sender home, with a jumper pack and wires. Hooked it up and when the water in the pot was boiling (roughly 210 F at my altitude), the gauge read in the read part of the gauge. Sure enough just like what every one said, aftermarket senders are terrible. Wish I never would have lost my original GM. Anyways, after spending 2 hours on the internet reading here and there, I had a few forums, including some old thread here recommend this site : http://www.lectriclimited.com/mainpage.htm Apparently they produce their senders to the original senders Ohm specs, so that they read correctly. If anyone else is having the same problem, this might be a place to go.