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bad gas milage

W

wilder9032

New member
my 06 grand prix is only getting average on the computer 17.7mpg is that normal? what could I do to get it better just cleaned the mas. it is the 3.8 liter base model
 


thats about right if u drive some city miles in there. and plus the weather might still be cold where you are. and winter gas.
also make sure you're up to date on a tune up.

and fyi, my car gets 17.7 too so no worries
 
ok great yeah im in buffalo ny so its been real cold the last four months. I just did a tune up before winter. thank you
 
plus did you clock your mileage using the tach and the amount of fuel put in or did you use the mpg on the instrument cluster as that thing can be terribly inaccurate...use miles divided by gallons and see if its the same
 
copperpacecar said:
plus did you clock your mileage using the tach and the amount of fuel put in or did you use the mpg on the instrument cluster as that thing can be terribly inaccurate...use miles divided by gallons and see if its the same
Click to expand...

either way i get the same number. my dic tends to be correct most of the time.
 
wilder9032 said:
my 06 grand prix is only getting average on the computer 17.7mpg is that normal? what could I do to get it better just cleaned the mas. it is the 3.8 liter base model
Click to expand...

When my '06 hit 70k, I was getting similar mileage. I cleaned the MAF, throttlebody, and replaced the sparkplugs. It now gets 26-28mpg. Always reset your average when you fill your tank so you can monitor it properly.
 


SlowNA06 said:
When my '06 hit 70k, I was getting similar mileage. I cleaned the MAF, throttlebody, and replaced the sparkplugs. It now gets 26-28mpg. Always reset your average when you fill your tank so you can monitor it properly.
Click to expand...

I did just do new plugs and cleaned the maf where is the throttlebody and whats the best way to clean it?
 
this is a throttle body

252_1.jpg

iac_01.jpg


See those pictures. that the throttle body, even tho these pic off the 97-03 car, you get the idea.

It at the end of the air duction for the intake from the air box. take it off and spray it will brake clean and wipe it off.
 


If you are getting less than 18mpg on a tank or two you have a problem, I was only able to get down to 18mpg two different times one was me trying to get a bad tank by driving like an ass all the time. The other tank was me running in SD mode doing some tuning.

What I would look for/do is:
Clean the MAF and TB (remove all sensors first)
Check for vacuum leaks
Replace the fuel filter
Replace the O2 sensor
Replace plugs and wires if they are old

BTW my car is NA so if you are supercharged I would figure the lowest mpg to get would be 16mpg.
 
My regal gs, supercharged, averages 23mpg, with 70percent highway 30percent city, and me occasionally driving like I have somewhere to be
 


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