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Jun 21, 2002 (5:37 am)
I bought a new 2002 Chevy Prizm. it has 700 miles on it. on the sticker, it say 40mpg on highway.
i've filled 3 tanks, and i'm only getting 32 mpg. this is 95% highway, no A/C, windows up, tire air pressure at factory recommendations, etc.
So how come i'm getting 20% less than what factory says i should be getting? And how to fix it???
Jun 21, 2002 (7:45 am)
is barely enough to get an accurate mileage reading, you're not driving all highway, and the engine isn't even broken in yet. This sounds just about right. If you are doing a lot of highway, the engine is not being broken in properly by driving at consistent highway speeds.
Jun 21, 2002 (7:46 am)
Are you using gas with additives, like ethanol? I've noticed a 4-5 mpg drop in my Honda when I use it. Give your engine a little time to break in, as well, before getting bent out of shape about the mpg.
Jun 21, 2002 (3:59 pm)
I have a '01 Corolla - auto with 4 speed - get about 40 MPG on the road and between 30-32 MPG in the city - how are you figuring your mileage? What octane gas are you using? The previous poster(s) are right - your mileage will improve as the engine breaks in -the reason I mentioned the octane is because I get better mileage using 89 versus 87 octane -
#5 of 18 Takes a while for engines to loosen up.
Jun 22, 2002 (2:52 am)
I've had engines that improved on fuel mileage for the first 10,000 miles, so relax, give it some time.
I have always noticed my best mileage is on 87 octane gas, use the lowest octane gas that does not knock, you throw money away otherwise.
#6 of 18 Break it in...
Jun 22, 2002 (8:38 am)
When my wife's truck finally broke in we both noticed it. We went nearly 40% farther on a tank of gas than usual, so just give it time. I didn't really figure it out for a while either, I thought the gauge had gotten stuck or something, it was amazing, for some reason all at once in the middle of a trip to our cabin it just settled down sealed up and stopped sucking gas, now it just sips it. Another thing with mileage ratings is that they are done with one skinny 95 pound person behind the wheel with no cargo at all. You might not ever get 40 MPG, but you should be close, unless you are hauling the family for a trip to the beach or doing a lot of car pooling.
#7 of 18 mpg in the world vs. EPA numbers
Jun 24, 2002 (5:34 am)
From the EPA website: (http://www.fueleconomy.gov/feg/info.shtml)
"The test simulates a 10-mile trip and averages 48 mph. The maximum speed is 60 mph. The test is run with the engine warmed up and has little idling time and no stops (except at the end of the test)."
If your driving isn't like this, you can expect different numbers even after your car is broken in. If your highway speed is like mine (75-80 mph), then getting 80% of the EPA may be reasonable.
It's also been my experience that as highway speed increases smaller/ higher RPM engine mpg drops more than bigger/ low RPM engine mpg does.
Finally, previous posts are correct, mpg will probably improve over the next 10k miles at least.
As an example, my recently-sold 1989 Firebird Formula 5.0 improved its mpg incrementally over the years, and was getting best-ever mileage this year.
#8 of 18 The 20% drop can also be accounted for by the ethanol-based fuel,
Jun 24, 2002 (6:19 am)
as mentioned by others. When I was a service manager, I rec'd several notices from major fuel companies to expect a 10-20% drop in fuel economy in the name of saving our environment.
It still isn't broken in, though, and won't get its best mileage for a while - I can't tell you the number of times I've had that argument with service customers.
Jun 25, 2002 (2:26 am)
I always get much better than EPA ratings on the highway. Remember that they subtract 22% from the actual test number to get the number that is posted on the car - this is to make up for real world people not matching the conditions they use.
Remember also that some cars with man trans are not in top gear at some of the speeds they drive at for the highway test - all cars with auto trans are in high gear. This is why the tests are biased towards automatics, and manuals can usually do better than EPA numbers while automatics have a harder time.
My Integra is EPA rated at 24/28. My highway mileage is always over 30 (if I drive 80-85) and is as high as 40 if I stay at 60 mph.
You might want to add more tire pressure that will help. Car makers usually reccommend too litte - just ask Ford Explorer owners. Call any tire shop and they will tell you to use at least 32 psi all around (sometimes 35) tires will last longer, be safer, and handle better as well as get better mileage. This is at the expense of some ride quality, and vibration isolation. Also always check tire pressure when the tires are cold.
#10 of 18 Re: ethanol
Jun 25, 2002 (2:28 am)
Ethanol has 1/2 the energy of gasoline. Therefore if you use 10% ethenol your mileage drops by 5%.
Oxegenated fuel is also bad for mileage.