I have a 2000 Plymouth Neon. My engine light is on and I am noticing that I am burning a lot of gas lately. I have been just going to work same as usual and I am burning an extra quarter tank or so of gas. For instance, usually to and from work I use 1/4 a tank, so 1/2 in two days. Now after 2 days, my tank is almost on on 3/4 tank left, almost on E. What is going on??

Have the engine scanned for codes.