[Alex3000GT]

Does your exhaust smell like unburnt fuel?

If so, check out your plugs and wires, when was the last time they were both replaced? If you don't know the answer, change them.

Also check for vacuum leaks with soapy water at every fitting along your intake system, preferably while your engine is still cold so you wont burn yourself when you rest your hand on valve cover..

Does the car sound really rough? Almost diesel-like. If so, I'd lean towards a bad MAF sensor or maybe just an unplugged MAF sensor.

How long ago did this problem arise? Was it gradual or suddenly? Is your check engine light on? What year is your car? (OBD1 testers are cheap and can pull engine codes).