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06 Maxx SS MPG

4672 Views 28 Replies 8 Participants Last post by  Alan06
My 2006 Malibu Maxx SS (3.9L V6) is averaging 13.67 mpg. My last fill up was 11.6 mpg!
I purchased this vehicle a month ago and track my mileage on every fill up. This is not the information coming from the computer, these are my calculations based on miles driven between fill ups.
I replaced the EVAP purge valve and got a new gas cap after a code. The CEL hasn't gone off since.

Any ideas on why the vehicle is getting HORRIBLE gas mileage?
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At 96k your due for plugs. Change the O2 sensors also, use only AC plugs and sensors, the upstream sensors that are closest to the engine as they control fuel mixture. There is no looking at the sensors to see how they are like a spark plug. O2 sensors get lazy / slow responding as the miles go on.
I've gotten back 2-3 mpg on putting in fresh O2 sensors.
Clean MAF
We all have been down this road and this is what has worked for us.
Is there any difference between O2 sensors? I'm seeing a Bosch @ $140 and a Walker @ $125. Does the extra $15 make a difference?
Use original AC brand O2 sensors only, other do not last or give issues. Bosch and Walker are junk.
Rock Auto has AC original sensors for less than $40 each.
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