Tech is pretty darn sharp with this stuff, if you do as he says, please let us know how everything works out. He has been an inspector for NHRA for years and has seen it all.
Did you replace the temp sender? And did you get the right sender? Does the car show signs of overheating, other than the temp sender? I found out the hard wa that there are many many temp senders, all created differently. They work on ohms for the particular gauge they are designed for.
"When I was younger, I could remember anything, whether it had happened or not." - Mark Twain