My 99' 3.4L 4x4 with just over 100k miles I get about 17-19mpg lately, usually closer to 17mpg when I'm driving in the city a lot. Sounds to me like you're about normal if you're driving in the city often, especially if you drive like me (heavy foot). Whoever told you 20-23 was nutts, I've never seen that mileage even on highway trips.