2006 Pontiac G6 transmission speed sensor

Hello, let me start by saying I do love my car! Ok we took a trip to the beach about a month ago which was about 3 hours away. On the way home I was driving on the interstate about 75 mph and tried to pass someone the car would just revive up and not go any faster. As I tried getting off the interstate to stop and check things out every time I pressed the gas it would to me like hesitate with slight jumping maybe, not sure if that's the best description sorry. Ooh wait I forgot the day before we left we had gassed up noticing my wonderful husband had stripped the gas cap leaving it stuck and having to be pried off! Not sure if that caused any damage or not. So after exiting the interstate we found the closest auto parts store which I then explained to the man about the gas cap he of course suggested we buy a new cap. We drove home and my car still was acting terrible. The check engine light never came on either. After getting home we changed the plugs and wires, cleaned the air filter, checking all fluids didn't change anything.

I had noticed my car had a rough idle burning a lot of gas and jerking real hard into first and second gear sometimes a few months a go before taking it to the beach. We had taking it to gm and they suggested a transmission flush and a few other things which had cost 500$ all together! The car seemed to be running a little better without the rough idle but was still only sometimes jerking into first and second gear. Sometimes the traction control light would come on as if I had turned it off.

So since the beach trip the car has not been the same at all. Burning a lot of gas. I never have problems starting it in the morning or anything. It always starts right up and goes. It when I'm at a good speed it will sputter or hesitate while accelerating. Some days it wont do it at all.

Someone told us to change the crankshaft sensor. While doing that we noticed a sensor with a broken or missing clamp for the wires and some of the wires were missing the protection tape stuff on the other part of it. Took it out noticing it was covered in black old oil or grease looked like. Wiped it off and put it back. After looking up that part I'm pretty sure its the transmission speed sensor. It was in the transmission.
That same day we went visit a friend. The car ran the same way just shitty with no change at all. When we left the car went into what seems to be limp home mode! Its not shifting at all wont go over 30 mph also making crazy noise.

. Thanks in advance :)