Started out with a problem with the park neutral safety switch going out which I hear is common with these transmissions. A month afterward only when you would floor it it would rev up in third gear and not shift out and the light would come on. If I pulled over and killed it then cranked it back up and drove it easy it would work just fine then the light would go off. Didn't drive it for 2 months because I got a company truck. Now I'm back in it and it seems to be having some hard shifts when I get on it. Also sometimes when I pull up to a red light and stop I feel the tranny shifting back down to 1st. it has 144,000 miles. I have only put 15000 miles on it and it was serviced at the dealership regularly according to records. Any suggestions?

If the check engine light is coming on you're setting codes. See if your dealer or an Autozone can read the codes from your transmission module and post them here. Once we know the codes we can hopefully tell you what's going on.