So I just noticed today that my MPG is sucking big time! Its never been great...but I had gotten it to about 19-20 mpg...and everything was going great...now all the sudden I happened to check it today and its down to 14-15! Ive been driving the same...any ideas on why it would drop so suddenly?
Thanks

 

other than engine tune...how about ****ty gas ?
Do you buy your fuel from the same location ?

 

I'm getting 14-15 in city, normal for me.... I guess.... there's no highways for me...

 

i buy it from spinx...but i do all city...and was getting 19-20...now 14-15...just kinda sucks...

 

Monitor it for a couple of gas tanks and see if it changes. Anyway 19/20 in the city a pretty darn good. I to mostly city and my combined average is between 14-16 MPG. The only way I can get near 20 MPG is if I do all highway/freeway.

 

Clean your MAF sensor with a bottle of MAF cleaner from Autozone. I noticed an average of 1-2mpg increase city and highway afterwards. I've been getting 21-23mpg with 60%city and 40%highway and 28-30mpg if im driving 100%highway cruising at 80mph.

But then again I have an SRT intake w/ ECU and Tanabe MT exhaust which helped increase my MPG by at least 4MPG combined.

 

i have an 01 GS3 with 131k on it and nothing but a k&n drop in and l-tuned axle back and i'm getting about 21mpg with probably 65-35 city to highway. Im assuming you're in either a 400 or 430. Try cleaning the maf as stated, throttle body, checking your air filter, checking your tire pressure, and if all else fails, check the spark plugs. If any have gone bad that will definitely make a huge difference.

 

ok...here is the run down...no mods...i was getting 15-17ish i put on a weapon r intake and a K&N cone filter, replaced the plugs, and just put on a hks hi-power exhaust...then i was getting about 19-20ish now...for no reason...and just this tank...dropped like 2-3 MPG...and i have a 98 GS3

 

lol, with intake and exhaust you've probably just been pedaling it to hear the sound.

 

Check the pumps labels when you fill up... MANY stations are starting to blend 10-15% Ethanol. This will punish your gas mileage.

I'm 85% highway and I regularly average 23-24 mpg per tank... the station I typically use went to a 15% E85 blend, and I could barely break 21. I promptly changed stations.

 

i think you mean 15% ethanol blend e85 is 85% ethanol and 15% gasoline...

 

errr... you're right. I suck.

I have E85 on the brain, since the local Evo and Supra guys constantly talking about it. Thanks for the correction.

 

search for a couple of jeffTsai's threads...

one of (if not the, i believe macd is comparable) the fastest GS's in existance outside of full race cars, and he runs on E85.