Today my engine temp needle went past hott then back down to cold-100 and its just laying on 100 now and not moving? anyone kno how to fix this... also not a BIG problem.... just for fun sometimes...... sometimes when I go to powerbrake the tires will spin good and fast and I can roast em... sometimes then barley spin and get going then... and sometimes they wont spin at all.... and a screeching noise comes from the rear end sometimes when I do it.. anyone any help please

 

Pull the green wire off the sender and ground it and watch the gauge. If it moves replace the sender.
Don't power brake!