I Dont know whats wrong with my car help!?

[Jamie]

ok i just bought a 95 dodge intrepid off my brothers friend whos a mechanic an when i got the car it was running great lately its been acting weird the other day i got in my car turned it on an when i put my car in drive it wouldnt go but it was on. so i turned it off then turned it back on an it started making a noise like i was pressing the gas but i wasnt. an today i was driving home from the store an it kept jerking while i was at a stop light? what could it be? if anyone knows please tell me