I had the exact same problem at 1500, even tried to put it on multiple inclines / declines thinking that was the problem. Ended up adding the 2 quarts back with Mobile 1, and brought to the dealer at about 4k. By searching the dealers in the area, I was able to find a bunch of oil service coupons. They confirmed over the phone that the coupon also applied to the Raptors ( thought they would charge extra for the addl quart). The deal was $39 for synthetic blend, and $59 for full synthetic ( both with the oem filter). I had the blend done, and just plan to have the service done at 5K intervals. At that price, it just isn't worth it to me to do it myself. Also dealer does their multipoint inspection and any warranty items at the same time.