Car reving when I'm not pressing on the peddle?

I have a 2006 ford 500. Today when I was parked I put the car in reverse to back out with my foot on the break to ease out, and the car revved like I was pushing on the gas peddle. It also happened two more times. Once when I was still backing out and once when I was pulling into my house to park. I tried to check the transmission fluid but apparently, after some research, I found out my car does not have a dip stick. What could this be? I don't know if it is worth noting we just put freon in our car because our air wasn't working and so we ve been pretty much running it on full blast since then

http://ricksfreeautorepairadvice.com/idle-speed-goes-up-and-down-or-high-idle/

Pedal, not "peddle." Cars have brakes, not "breaks." The brand name, the family name of Mr. Henry Ford, is a proper name. In English, all proper names must be capitalized. Please do so. Ford, not "ford." Punctuation. All sentences must end with a proper punctuation mark. US kids apparently wish not to learn rules of writing. The last sentence is not completed as if you fell asleep. As to the Ford 500. This is an extremely dangerous condition that has nothing to do with the AC nor much of anything else. The science is too complex and the car systems even more so. Mechanics are the professionals that repair vehicles. Texting over car is futile and a waste of time. You need an auto repair shop and I would not drive the car there. I recommend a tow truck.

I would check if there are any tsbs (technical service bulletins ) that are issued on your vehicle, either online or at your local dealership. Then I would take a quick look under the hood to make sure that no vacuum lines have been broken or miraculously came off their proper fitting. Other than that, see if the heat/ defrost selector or the a/c switch plays a role in this surging. It should raise the idle when you turn on the a/c OR select the defrost position on your heater control, and then intermittently when the a/c compressor clutch kicks in. That would be considered somewhat normal operation if so. If its more than normal, get your engine checked for service codes or fault codes.