i have a 1997 pontiac grand am gt 3.1 v-6 and i need to improve gas miledge?

[scott b]

i am a mechanic so i have replaced plugs coils and air filter fuel filter and still not beter im getiing bout 16 and im not hard on my car

 

[zack o]

have you tested your o2 sensor a sluggish o2 will kill economy in 97 a sluggish o2 will not set a code. will your o2 go above 750 milivolts?

 

[a19bk66]

i have a monte carlo with same size motor in it what i did i split the exhaust after the re burner put 2 1/2 inch out the rear it helped mine about 2mls per gallon

 

[Solar Max]

My 1995 does 24 around town and 30 on the highway at 75-80 mph.

I had a vacuum leak at one point that caused some mileage drops though.

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[Zimgxp]

Tire pressure.