If you don't have any codes, you might want to check your vacuum hoses to see if any are leaking. Makes a big difference in the way the car runs.
Or, guess it could just be time to tune it up.
Another thing which often occurs this time of year, water condensation in your gas. I run gas treatment a couple times each winter just to blow out whatever water there may be in the tank.
Stock 1987 Legend LS Coupe 180k (11/07)