I had found my problem as well
It was bad engine ground

So my mpgs are going down hill for some reason. Just replaced my alternator an ever since then I im losing about 100 miles a tank or more. the car smells of fuel pretty bad and theres quite a bit of smoke that comes out when I give it some gas.
My mechanic said possibly maf or ecu. And I doubt its the piping again because the power is still there. So any help thanks guys

bump please still need help

HELP ME PLEASE
Just had alternator checked and its fine, maf has been cleaned and it is fine. I need help on what to check for. this is my daily and i am putting in so much money for gas please help!

still looking for help guys, my mechanic suspects engine coolant temp sensor an it is causing me to run super rich.. any ideas?