My 1992 xj 4.0 is using one quart of oil about every 250 miles,more than that if i put a lot of highway miles on it. It has 180,000 miles on it. I did a compression test about 6 months ago,and all cylinders were between 130-140 psi and the plugs weren't oil covered,they looked normal. i am planning on doing some bolt on upgrades to sqeeze a few more ponies out of it before long,but I don't want to do it if the engine is toast. I know these engines are good for a lot of miles,but my xj shows signs of previous owner neglect. so the question is: Is there a way to tell if the blowby is the ccv problem,or something more serious? I have noticed the engine smokes on start up,but from what i can tell it doesn't smoke while i am driving it,and it still seems to have quite a bit of power. . thanks for the help,Ben