drop in gas mileage

[02silvz71]

Recently dropped about 100 mpg on 02 1500 silverado z71-Replaced air and fuel filter and cleaned intake before loss-Thinking oxygen censors.Any stories or suggestions would be helpful. thanks

[AG Bill 05 Z71]

Can you clarify what your drop in mileage really is? I think you are saying that you used to get something like 300 miles per tank full of gas and now you only get 200 miles/tank...(a drop of 100 miles per tank, not MPG).

 

You have a good guess that it might be the oxygen sensors going bad. Have you seen any "Service Engine Soon" lights or downloaded any DTCs yet? These diagnostic trouble codes would really help to pin point your possible problem. The oxygen sensors are $125 a pop (and you have 4 of them) so you don't want to replace them unless they are the problem...

[Bish]

Can you clarify what your drop in mileage really is?  I think you are saying that you used to get something like 300 miles per tank full of gas and now you only get 200 miles/tank...(a drop of 100 miles per tank, not MPG).

 

You have a good guess that it might be the oxygen sensors going bad.  Have you seen any "Service Engine Soon" lights or downloaded any DTCs yet?  These diagnostic trouble codes would really help to pin point your possible problem.  The oxygen sensors are $125 a pop (and you have 4 of them) so you don't want to replace them unless they are the problem...

 

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Agreed it would help if you gave specific detail on the drop. On my Tahoe, I started loosing around 2 MPG as my O2 sensors got "lazy" No codes thrown but mileage went back up as soon as I replaced them. BTW-Only replace the before cat sensors as the after cat are only there to signle cat failure and has nothing to do with air/fuel mixtyre.

[fyarbrou]

Yep, Bish is a sharp cookie! Only the "before catalytic converter" O2 sensors have any influence over the air/fuel ratio.

 

Fred

[allenmehrer]

clean your k&n often, it helps, especially in the spring with all those little bugs everywhere