Mets231

Since having my 05 corvette. I have noticed that I am only getting around 8.9 miles to the gallon. This is city driving. I have been running 91 octane with a mixture of 100 octane. 5 gallons of 100 and the rest 91 . 91 octane $3.29 a gallon the 100 octane $9.99 per gallon. Should my car be getting better gas mileage? If so what could be wrong. Tuneup?

919cw313

Why are you mixing? It will run fine on 91.

2008 Corvette

Why are you using blended gas ? The 91 should be all you need. Try that first. 08 LS3 around town I get 22 to 24 depending how I drive.

Mets231

I mixed to try to get better performance, but maybe all that is happening is terrible gas mileage. I wanted to run 93 octane, but can't get it here. So by mixing it will raise the octane. Next fill up I will run 91 and see what happens.

Bruze

Forget the octane, it won't make any noticeable difference.

If you're truly getting 8.9 MPG there is something wrong. Double check the computer's numbers by figuring it the old-fashioned way.

RobLo

I run 93 in my stock '05 but the manual recommends 91 and I've run that in the past with no problems. My mileage, 70% highway, 30% city is around 20-22, unless you're a jackrabbit you should be doing much better then 8.9 even in all city driving...good luck!

ProCycle

My worst tank over the last year was about twice that. Unless you are flogging the car all the time there is some kind of problem that needs to be addressed. Maybe a bad coolant temperature sensor, maybe some leaky injectors. It's not something a 'tuneup' is going to cure. Someone needs to get in and do some diagnostics. That much extra fuel is likely washing lubrication off the cylinder walls and carboning up the combustion chambers.

HOXXOH

Hopefully the 100 wasn't leaded that clogged the cats, causing the poor mileage.

EVRose

I do mostly city driving in my 05 with A4. My average mpg is 20 using 91 octane.

MidYearRoadster

Too much octane can work against a lower compression engine. just use the octane the factory suggests and if your mileage does not improve drastically then you have a Problem.....

jrose7004

I get a little bit better than 20 around town. So you've got a problem somewhere.

ben z

Mine's an LS3 ('08) manual, I only get around 15mpg in town. Flat roads, temps in the 70s-80s, but I think it's a combo of the A/C always being on, and lots of traffic and stoplights with long waits idling. I use 93 octane. Around here it's either that or 89 or have to mix each time. And everything here is at least 10% ethanol, which lowers mpgs. But 8.9 sounds extremely low unless driven really hard.

Sunnyvale Dave

My mileage in city driving is in the teens. I have found my Corvette doesn't do well in stop and go driving. Your mileage is the lowest I've seen. I don't know how guys that claim they get 20 MPG in the city do it.

Before I retired, my commute to work was 6 miles. My car didn't get much time to warm up, and there were about 20 traffic lights. I went through a gallon a day on that 12 mile round trip commute.

bassman50

With 91 octane, our '07 base with the A6 is averaging about 18 - 20 MPG in our local area (mountainous terrain) from what I can tell. I take it pretty easy though. . . .

Steve

LMB-Z

You just got the car the 19th of February. Do you floor it every time you start? No way that car should get 8 mpg. I think you need to refigure your gas mileage. Have you read the owners manual???

65GGvert

I'd set up a video camera to see who's stealing gas out of your car.

J3TVETTE

Also 08 Manual. I see around 17mpg city and 27ish highway. 8.9 is out of like for sure.

wayback

I'm thinking a lead foot. Only way to get that bad of milage is to thrash it all the time.

As others have said higher octane wont help at all. Octane rating is for preventing knock or pre-detination. Higher compression motors need higher octane. Has nothing to do with milage or extra power.

Vette_DD

About 99% of my driving with my 012 coupe is in town and I get about 15 MPG if I don't use the paddles or get on the gas a little. I do use 93 octane Kroger gas.

*Trip*

2012 stick shift.... Driving normal in town, shifting 1,3,5...i get 20+..... Blasting around, maybe 12..... Steady freeway..... Around 30 mpg..... Hauling *** freeway 24