Sounds like a vaccum leak or possible misfire issue. Do you have a check engine light on? If so do you know the codes/ or could get it scanned? That would give us a good starting point for diagnoses. How does the car run off idle? Let me know, and any more details you can think of, past repairs, anything you've done, etc.
Wednesday, August 17th, 2011 AT 9:45 PM