At least I'm not the only one with bad mpg I thought something was wrong with my car? Guess it really depends on where you drive and how much is stop and go... I'm planning on doing a tune up when I get some money, the car does almost have 103k miles so I don't know when the last time its been done. It could be affecting the performance some.... Thanks again!

 

Same here!

 

I use 6th gear typically anytime I'm just cruising over 45MPH for an extended period of time. Seems like I get the best gas mileage in 6th at right around 50-55 (29ish). Mine is a ZO6, however, so I have don't have as tall a 6th gear as the base 6 speed.

Average for city / highway driving (mostly city), is 20-22.

 

I average about 16-17MPG overall driving it like I want. I can get 23-24 on the highway. I have an M12 (Z06) transmission and 3.90's. I also have 577RWHP out of a 427. I usually cruise at 1700-2000rpm - whatever gear that is.

 

^ That thing must be a blast to drive! 577WHP and 3.90s, in what I'm assuming is a NA 427? Wow!

 

could be the engine is a bit dirty too.

Put in a tank of fresh 91 or 93, take a highway run 65-70 mph for a FULL tank. That will help clean out the gunk.

next tank should be better fuel mileage around town.

 

Hey Batmobile-
You're 20 and you've gone thru an S2000 and now the C5; methinks that you are doing OK. Worried about mpg? You are driving specialty performance cars and in town mileage always suffers big time. Don't take this wrong, but at 20 and a college student, you should have known that. There's lots of things that I didn't know at 20 so keep asking but remember, do your homework first.

 

I average around 20MPH city and highway on my 03 Z06.

But I do push it sometimes. Just can't help it, this Z06 is a blast to drive!

On the highway, I get around 28 MPH at 80 MPH. Just keep in mind that running at night with headlights up, is going to drop your mileage about 2-3 MPG. Those things catch a lot of wind.

 

I average about 29-30 m.p.g. on the highway with the 3.15 gears [automatic] w/LongTube headers, blackwing and tune! I drive like a really old Lady according to my wife! She however gets all the speeding tickets in the family and I have never had a moving violation in my 50 years of driving!

 

gotta give this a shot too!! thanks

 

With the 427 in my C5 (3.73 gears, 6-speed) I get about 19-20 city/rural and 26+ on the highway. I have gotten over 30 when driving very mellow. I got about 2 more mpg when it was stock, or supercharged, or heads/cam/supercharged...

 

I use just about every gear when driving in the city and I dont ever drop be low 18 mpg, Im usually right at 18.8 or so and if I baby it I can get upper 19's to 20. Thats also with a lot of trips that I dont even get the car up to temperature so it really suffers there. Another thing I dont find a problem with putting it in 6th at 45 just as long as you are easy on the pedal it wont bog down and will cruise right along and when I skip gears its usually 3rd, 4th, and some times 5th so Im going from 2nd to 5th or 6th.

 

Mine is an automatic, stock 03. I get 16 in town and 28 on the interstate at 73 mph.

 

I average 15-17mpg in the city with moderate to aggressive driving. the lowest i see is 14-15. Even if i try to drive fuel efficient its never really above 17. Lower rpms doesn't always equal better fuel economy, you have to find the sweet spot where where the engine load is less and you are off the throttle more than on it. On a trip from la to san diego i cruised there about 85 the whole way in 6th gear about 2200 and averaged about 33 mpg, on the way back i was trying to "conserve fuel" and was cruising at about 70 in 6th and found myself on the gas a bit harder to maintain my speed and averaged about 29mpg on the trip home.

 

I've always averaged about 32 mpg on my roadtrips. I average 25 around town. Shoot , I put it in 6'th when just going about 40mph. I just like to keep it around 1k rpm's. No lower.

 

We are driving a performance machine. Why are we worried about mpg? So worried , in fact, that lugging the motor is necessary? We hear about how horrid it is to have garage queens? What about driving at 40 mph or below in 6th gear. The automatic first to fourth gear has an aftermarket to defeat that annoyance. It was designed to increase mpg for the EPA. So lugging is OK? I don't think so, but I'm no expert; is there a tech expert out there with evidence that what is being advocated here is OK?

 

Jeez, I thought everybody on here was a "tech expert". You would think. Just drive your car like you want, and don't worry, be happy.

 

Ill probably get flack on this,,but it does depend a lot on the type terrain your city has. I've been driving sticks for more years than many here have been alive.Where I live we have some very long streets with little elevation change(read FLAT stretches) I have driven (with very litte throttle) as low as 25-30 in 6th. Now I know when it is lugging(I'm not under these conditions) and I have checked the gauges (digital & analog) and it is still running 30-35# oil pressure. I too skip gears etc. and manage low 20's in city driving! Most of the time traffic prohibits "enthusiastic" driving anyhow. AND,,,just so you guys don"t think I'm just some old fart that putts around all the time I have regularly turned LOW 13's (a best of 13.08/110.24) with reaction times as low as .001 . I also have on occasion kicked it up to 105 on the interstate to clear vehicular cluster f**ks! With these cars you CAN have your cake and eat it too!!

 

i've own my vette for about 3 years now and i've never seen below 19mpg.

I drive it 100% city driving to and from work every day. I usually see anywhere between 21-22 mpg. on the DIC it shows 23 mpg. I always calculate out my "real mpg". If i drive combination i get about 24-26. Highway only i can see 28 easy...These are also w/ a few small punches in the throttle here and there. Best thing for gas milage is to not slam on the throttle OR brakes. Ease into it. just think the more you slow down the more you have to speed up. the more constant you are with your speed means better gas mileage because you don't have to have constant throttle being applied.

Your shifting methods seem pretty good. I never use 6th unless i'm going in the high approx 48+. I'd calculate your real MPG and see if it's matching your DIC's 14mpg. If it is and you don't drive it like you stole it (or have cam upgrades or other high hp upgrades) then i think you need a new tune.

Terrain does play a part in your mpg. just always keep in mind that the more you're on the gas, the more gas you're using. So if you're going uphill all the time you will definitely be using more gas than if you're going downhill. Also another that people don't think about is idle time that's a HUGE gas guzzler.

I've tried many different methods of shifting. Going from 1st-3rd. 1st-4th, 2nd-4th etc.... for me i drive 1-2-3-4-5-6 and i still see 20+ ALL the time. Sometimes i go 1-3, but that's a rare occasion.

I hope this helps. I see that a tune might do you wonders or o2 sensors might need some attention.