2001 Dodge Neon Transmission?

Ok so if I don't slow down enough before stopping and I mean wayyy down or sometimes it doesn't matter the car will shake extremely bad and I'll have to throw it into second gear to get it to even stop, also every now and then after taking a turn or going up hill or really whenever the car feels like it the gas pedal will basically be useless it won't accelerate the rpms don't even move I usually have to pull over and put it in park to stop this or put it Into second gear for a few seconds also the car takes awhile to shift this might be normal but I'm just NOT SURE! I bought the car just yesterday the check engine light IS on but I can't remember the code exactly the guy told me a chipmunk had chewed a wire to the O2 censor I think. Now if he was telling the truth could ALL this be being caused by the wire? If not what is it from? Thank you!