1998 dodge avenger 2.5 reving problems?

[Donald]

ok yeah it sounds weird but this car is killing me , but it has sentimental value so hear it goes when you are going down the street and you stomp the pedal on the floor it acts like it has a revlimiter in it which it has never done before it will get up to 4000 rpms and start reving up and down real fast but will not go over 4000 rpms i just need some expert advice because it sounds to me like it is the map sensor which costs 99 dollars but i want some expert answers to help me because once i buy the part and put it on then i own it and i cant take it back thanks