Thread: Issues with Gas Mileage .. what to do

I just got my 2002 grand prix gt and my gas mileage is really bad .. I hardly make 400 KM's with a full tank which is almost ~16 L / 100 KM. Can somebody suggest what should i do ?

Before you comment let me give you some history about my car ... My car had some MAF sensor issue which resulted in getting my car turned off while i am driving. I took off the MAF sensor (since i wasn't sure if its MAF sensor which is causing the issue or MAP sensor). Without MAF sensor my car worked fine with its mileage at 20 L / 100 KM. I got an after market MAF sensor and sicne then its mileage is around 16L. Before i replaced the after market MAF sensor, I was getting ~ 14 L/100 KM.

I have been reading around and i read that after market MAF sensor has issues but i am not sure from where to get a good MAF sensor.

Can any body help ?

P.S:
btw, I am in GTA region, Canada.

Did you drive mostly in city or highway? My 05 GP base model get pretty bad gas mileage in city driving. I got about 16-17 miles per gallon in city, which is around 14-15 L/100KM. My trip is usually 3-4 miles to work so I guess it is pretty bad for gas mileage. But when I go on highway, I get 27-28 miles per gallon (8.5-9 L/100KM). So if you drive mostly short city trip, 16L/100KM is probably not that bad. I supposed gas mileage on 02 and 05 are not that different.

It could be the aftermarket MAF sensor. You can try AC Delco MAF to see if it helps. You probably can get them from Amazon or other online retailers for not too expensive price. If you have a code reader that can show live data, you might look at the fuel trim, air fuel ratio and other related stats of your car. This might give you some insights into the gas mileage issue.

Originally Posted by Chadgervais

When it comes to sensors in these cars, AC Delco really is the only way to go. The computers in these cars are really sensitive to even the slightest inconsistency in aftermarket parts, heck even the interface module for an aftermarket radio has to be just right or the PCM shuts down and kills your gauges and cooling fans.

As for gas mileage, you live in the north and its winter time. A cold engine is less efficient than a warm one. On the highway, you get up to temp and stay there, in the city, driving only a couple miles to work, your engine does not fully warm up. Right now Im getting about 18 in town and 28 on the highway, during the summer i get 22/31.

I totally agree. When it comes to electrical replacement parts, AC Delco should be the first choice. Our cars are somehow pretty selective on sensors.

Thanks guys for the comments.

- I have been measuring my fuel consumption from September. so its not really winter thing
- For highway, I get almost 500 KM in a tank which is ~11 L/100 KM. Really good but not as good as my 2001 Grand AM.

I am okay with this mileage as long as i am keeping my Grand Prix. The only thing which i want to make sure is that if its the normal mileage or my grand prix has some issue