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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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Also make sure your tire pressure is up and correct.... makes a difference even on short highway jaunts for me and my 3.5.

I cant believe they consume that much more.... wonder if they have significantly different tire sizes.... in my 85 montecarlo..... I had 245 60 15 all the way around.... swapped to stock 195's?... made a huge difference in milage for me.

My 3.5 JUST averaged 7.8 l/100km on a 260 km trip 3 days ago.... and i have a maf code and busted up loud exhaust. ... pure highway. ... 87 octane. I am around 11.5 to 12 for pure city driving.

Some great suggestions above.... ya ypu want the best milage... gotta get a bit finky with maintenance
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.
X2 on bosch o2 being junk.... in my other life (Camaro tech) bosch o2's are junk.... we in that application use ngk ....if i remember correctly or denso...
Oil smell coming in the vents , is usually someone spillled a little oil on top up or change....if thats not the case
Here we go......
You are leaking oil ...its running on the manifold somehow. You changes the evap solenoid....was this hecause you have a code saying vacuum problem? I am guessing possible gasket faliure hense the oil leak....and the smell of oil... it can contribute to bad milage aswell....... this is a guess ,but with your symptoms it makes sense
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Good photo ,nice to know
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