Ive got a 98 svt contour with a 2.5 v6 in it and when I bought it it had excellent gas milage. Now its droped by about 6-8 miles per gallon and I noticed my exhaust sounded a little bit louder. I dont know much about efi, I drive an 84 302 mostly. Could the timing be off, or is this not possible because a comp controls it. Would new plugs and wires help? What sensors could be bad? Also the check engine light is on.