Camry burns too much gas , no check engine light.

How many kms? There is a couple things that help with milage.. Fresh plugs, fresh filter and even fuel filter... We find that alot of our used get better milage once we change all filters and plugs.. or your O2 sensors but they usually throw a code, we have seen where its so slight it just stores the code and does not turn the chq engine light on... hope this helps

Planet kia. Thanks. But its low mileage only 67000 miles. I've changed airfilter and and spark plugs. Same issues still. I'm losing hope. I'll try to replace 02 sensor. Also Someone had told me something about fuel trim or something..not sure what that means or if that's the problem.