99 Stratus 4 cyl

Car will not go over 30 MPH. I have no idea why! It is not my car but the car idles properly. It is just having a hard time getting up to 30 MPH. My guess is "hard time" means the gas pedal is to the floor and it is not being very responsive. ANY Ideas?? NO engine light or codes, there is a hole in the cat but it is not clogged and wed have a MIL.