Verify the VIN number. Some slimy dealers will list a car and adjust the VIN by 1 number and the only information is what they start and going forward. Good way to make a dirty car look clean on carfax.
Found a dealer doing that on a Genesis I was looking at. I called the out on it and after the initial deny they stopped replaying. I reported it to Carfax as they are starting to learn of this scam.
Look at the 17k Genesis carfax here...
http://www.liainfiniti.com/used-inv...ius=false&showSubmit=true&showSelections=true
Notice how the only thing listed is what the dealer selling it reported. Now compare its VIN to the other 2009 they have. Notice how the 4 should be a U in the first 2009 car, that's the difference. The correct VIN has 30 records.