Hey scotty I get 19 mpg on the highway ( which is high for my car) but 6mpg in city driving. I have a 1988 Mercedes Benz 560 SL
Those v8s are heavy gas drinkers. The body are heavy and sometimes the first shift stays in to long, there is adjustment but a lite foot is best. Around town best you can hope for is 12 mpg. Make sure tires are inflated properly. Also caliper are not hanging up.