I just got a 99 sport with 186000 on it it runs good, needs the cam o rings replaced i believe, but i filled it up the day i got it and i have 183 miles on it and its at less then 1/4 tank already so im estimating 4-5 gallons so thats about 10-11 miles per gallon by the time its empty maybe??? 50 miles were highway the rest was city and its been below 0 here the last few days but im not very impressed, the guy i bought it from claimed 20mpg, so any ideas on whats going on or any other info????

 

If you're getting that low, sounds like it needs a major tune up. 20 MPG is achievable if you baby it. I average around 17 MPG with TC-W3 additive. Did you ask what brand/octane the PO was using?