Poor City Gas Mileage

**Johns00Z28** · 09-04-2007, 04:38 PM

Not sure if this is the right section to post this but here goes. I just came back from a little road trip this weekend where I drove 3 hours one way on the highway. My gas mileage was terrific, in the neighborhood of 30mpg. But when I drive to work, which is only a couple miles away or around town it just seems to suck down gas, maybe 12-15mpg. I wasn't sure if that was because it was an automatic. I have no mods done to the car at the moment and I don't rag on it everywhere I go either. Just wondering if anyone else gets great highway miles but terrible city miles?

**firesilver** · 09-04-2007, 05:52 PM

i think its cause really short trips dont allow the engine to warm up enough to where it gets the best gas milage at.

**Johns00Z28** · 09-04-2007, 05:54 PM

Well I could understand that for the winter time maybe but in the summer it's warmed up in a couple mins.

**airmaxon1** · 09-05-2007, 11:05 AM

Originally Posted by Johns00Z28

Well I could understand that for the winter time maybe but in the summer it's warmed up in a couple mins.

I have the same exact problem, just had a 3 hour one way road trip, and got around 27 mpg. But now back in city going to school and work im back down to 11-13 mpg. Ive been told many times its because of the short trips like firesilver said, and starting and stopping in city also kills it.

**firesilver** · 09-05-2007, 12:13 PM

yeah cause if its only 3 miles it probley doesnt warm up until the last one.

**Johns00Z28** · 09-05-2007, 09:23 PM

So if I start it up and let it warm up prior to driving it, it should get better gas mileage then?

**firemedic0135** · 09-05-2007, 09:46 PM

Originally Posted by firesilver

i think its cause really short trips dont allow the engine to warm up enough to where it gets the best gas milage at.

That is the most assanine comment ever.

It is because you are using more throttle and rpms to get the car from standstill to speed.It is completely normal and not far from the GM specs.

Think of it this way if you are cruising down the highway at 80 mph and you are taching about 2000 rpm's
compared to going 35mph at 2000 rpm in town you are running the engine at the same speeds but going nowhere near the same speeds toward your destination.

Engine warmup has Lil to No effect on Mileage.

**Johns00Z28** · 09-05-2007, 10:13 PM

So is there anything we can do to make our cars a bit more fuel efficient in stop and go driving? I wouldn't mind getting 12mpg if my car was making 600hp but I do mind since it's stock...lol

**JonB** · 09-06-2007, 07:14 AM

Short trips you will get bad gas milage period. I use to have the same problem, work was only 1 mile from my house was getting 17-18mpg in my m6 now I live 12 miles away and get 22mpg and this is all in town driving stop and go. Allowing you car to warm up will not help gas milage all your doing is wasting gas. I don't recomend getting in and hauling ass but leting it warm up for 10 min is a waste of gas. The biggest thing I can recomend is cuting out short trips if possible. If you need something stop on your way to work or on the way home when your car is already warmed up. Also make sure your car is in top shape plugs,wires,fuel filter,air filter,injector clener, fresh fluid in everything proper tire pressure ect.

**Firebirdjones** · 09-06-2007, 07:32 AM

I have both an auto and a 6 speed 4th gen and both cars do very well around town.
My auto gets 20 mpg consistently driving around town here. My wife drives the 6 speed to work everyday (stop and go) and gets 21 mpg with it.

On the highway my 6 speed has gotten a best of 27 mpg driving 80 mph. So your 30 mpg with an auto is phenominal,,,,I would say,,,because my auto 4th gen won't even come close to my 6 speed 4th gen when it comes to mileage on the highway due to the .50 overdrive on the 6 speed where as the auto only has a .70 overdrive and spins roughly 400 more rpm more at the same speeds. Around the city they are very very close though.

**slims00ls1z28** · 09-06-2007, 09:09 AM

sounds about right you must have the 2.73 gear in your auto. normally mine got around 28 mpg in a city/highway mix going too and from to work. Straight highway drives would net me 30+. But stop and go wil most assuredly knock you down some. Hows your driving style? When you take off from a light are you always in front or just easy casual? That will have alot to do with it.

**Y2KPewterSS** · 09-06-2007, 09:32 AM

Originally Posted by JonB

Short trips you will get bad gas milage period. I use to have the same problem, work was only 1 mile from my house was getting 17-18mpg in my m6 now I live 12 miles away and get 22mpg and this is all in town driving stop and go. Allowing you car to warm up will not help gas milage all your doing is wasting gas. I don't recomend getting in and hauling ass but leting it warm up for 10 min is a waste of gas. The biggest thing I can recomend is cuting out short trips if possible. If you need something stop on your way to work or on the way home when your car is already warmed up. Also make sure your car is in top shape plugs,wires,fuel filter,air filter,injector clener, fresh fluid in everything proper tire pressure ect.

Very good advice

**firesilver** · 09-06-2007, 12:11 PM

Originally Posted by firemedic0135

That is the most assanine comment ever.

It is because you are using more throttle and rpms to get the car from standstill to speed.It is completely normal and not far from the GM specs.

Think of it this way if you are cruising down the highway at 80 mph and you are taching about 2000 rpm's
compared to going 35mph at 2000 rpm in town you are running the engine at the same speeds but going nowhere near the same speeds toward your destination.

Engine warmup has Lil to No effect on Mileage.

First off you didnt even spell asinine right.

Im about 90% sure your car runs richer when you first start your car or until it warms up, giving you worse mpg. Also your oil, tranny fluid, rear end fluid is thicker when its not up to operating temperature creating more drag on your engine. I think its a combination of not being warmed up and stop and go city traffic.

also i think everyone one here understands that you get better mpg at highway speeds. we are just wondering why he only gets 12mpg when your suppose to get 16-18mpg in the city.

**Johns00Z28** · 09-06-2007, 01:56 PM

Originally Posted by slims00ls1z28

sounds about right you must have the 2.73 gear in your auto. normally mine got around 28 mpg in a city/highway mix going too and from to work. Straight highway drives would net me 30+. But stop and go wil most assuredly knock you down some. Hows your driving style? When you take off from a light are you always in front or just easy casual? That will have alot to do with it.

I would say I usually drive fairly conservative. The car shifts at or before 3K rpms most times. I understand when I'm getting into it that it'll suck down considerably more fuel but I don't drive like that regularly. I do usually pull ahead of most traffic when I'm at a light but it pulls with ease and like I said I'm not winding it out. Is there a way to check what gear is in it?