Paramus Chevrolet

I was experiencing a problem with my 2009 Aveo; the car started losing power while driving and no matter how much gas I gave it, it would not drive faster than 15-20 mph; the check engine light would come on after the loss of power and remained on. I would had to stop, shut off the car, wait a couple of minutes and start it up again, in order to regain full power (The check engine light would remain on); this started a year ago, and when I brought the car for service, they could not find the problem; they would reset some codes, the check light would go off, and the problem would go away. A year later, with the cold winter, the problem came back and with the same result; the dealer had no idea what was causing it. Finally they told me it needed $2000 worth of repairs to fix the issue; I went along with it and got it done; a week later, the car lost power again; they checked it and now they told me it needed additional $500 to fix the throtle body; I spoke with the manager and he kept insiting that the check engine light was on because a different issue was present; however, that was not the reason I got $2000 worth of repairs.. it was to fix the lost of power, which would cause the check engine light to come on... I believe the car should be fixed at no additional charge, since the problem is still present, which means that whatever was done to it did not fix it and it was probably not needed.. the manage wants me to pay for the additional repairs at a discounted price, but he does not guarantee it is going ot fix the probelm... The people at the dealer were very nice and friendly, but I don't belive they took care of my problem at all...