Would an O2 sensor cause you to go through a lot of gas and make the check engine light come on?

Answer 1

It is a very broad answer for why your engine light is on. He is probably right that is on due to the oxygen sensor but as for the gas mileage statement. If you haven't changed your pcv valve, that can kill your mileage as well, but it won't cause your engine light to come on. If you are experiencing hesistation in your acceleration, it may be a bad mass air flow sensor and that will cause your engine light to come on and kill gas mileage. I personally have run my vehicle with a bad 02 sensor and passed my state emissions test. So kudos to me. But I also use Slick 50 High Mileage Fuel System Cleaner. This stuff made the engine light go off after a full tank of gas with it mixed in. It cleaned the intake manifolds well enough to deactivate the check engine light. So if you want to put off a potentially couple hundred dollar repair, try the product first. I recommend anyone with an oxygen sensor engine light try this before replacement. It works. I have used it first had on my 2002 Dodge Dakota 4.7L V8. Good Luck, oh, it costs about 8-10 bucks for that slick 50 stuff, worth it though.