certified used is the biggest bunch of horse manure i've heard yet. they are just certifying that it is used and there were no visible problems according to some underpaid "tech" usually. it's a used car and you don't know how it was used. it may have been a rental car for all you know & with that said i'll remind you that buying a used rental car is like marrying a prostitute. car fax is a joke at best, i know guys that have nearly totaled a car and put it back together in their garage, made it look nice and sold it with a clean car fax. if the insurance or department of motor vehicles doesn't know about it then car fax doesn't know about it. my jeep, when i checked the car fax was registered to the same owner 4 times in 3 years... didn't make any sense. it had visibly been wrecked and repainted but car fax was clean. you might check on "lemon laws" in your area. i know my sister had a lot of problems with a car but in california it was a 3 strike lemon law. you would have to take it to the dealer for documented repair and if it wasn't corrected the third time you would be able to claim it as a lemon for an exchange but not for a return. i also had a nice chevy silverado with a clean car fax that i bought used from midway chevy in phoenix. i drove it a couple years and when i was selling it the buyer's financier said they couldn't finance the whole amount because it was officially classified as a "lemon" due to some uncorrected fault.

sad but true.