When i bought my 1995 cadillac deville its avg mpg was 11.2 it went up to 12.4 and now its down to 11.0 should i be conserned if so what can i do yo fix this

Hi There: Make sure you check your state of tune on your vehicle also fuel filter and air filters etc. make sure you tire pressure is correct and ultimately you may have carb problems possibly gumming up a bit. Hope this helps Sincerely Ultimate Performance Team