Why am I getting bad gas mileage?

Question

I understand that improperly inflated tires effects mileage. I recently had a flat, and got a brand new tire on my front left wheel. My car always guided slightly to the right, alignment or whatever, but not very noticeable. Now after the tire change my car pulls alot more to the right, and it is a tad annoying. I noticed my gas mileage today, its a little past the first 8th from a full tank. I always get from 88 to 100 miles on the first 8th, now its slightly past it and its at only 58 miles. So there has to be something severely wrong here. I'm driving about 200 miles this weekend, so I can get a better judgment. I figured maybe the front right tire is not properly inflated. Does a brand new tire and an older tire together effect mileage too? Thanks for the help

Answer 1

If you have radial tires, you should not replace just one tire. If the flat was in the front, both front tires should have been replaced. Diameters of the tires affect handling and steering.

To check your gas mileage, you have to be more scientific. First, fill up your gas tank and record the mileage on the odometer. Run your car until you are near empty. Again fill up the tank, record the number of gallons. Again make note of the miles on the odometer. Subtract the lower odometer reading from the higher, then divide by the number of gallons from the second purchase. That gives you miles per gallon. I assure you it will be less than the published rating for your vehicle. The EPA test is flawed.

Answer 2

You need to have the alignment checked before you drive 200 miles. If you have an alignment problem you could ruin both front tires in that distance.

Your mileage problem likely has nothing to do with a new tire. I would let it go for a couple of tanks, and keep track of what you really get. The gauge is not terribly accurate. If, after two tanks of gas, you find you truly not getting the mileage you should, have a mechanic look at your car. It could be anything from a vacuum leak to a bad sensor to needing a tuneup.

Answer 3

normally you would replace two tires at a time (the front or back pair) this helps with keeping alignment and mileage. Sounds like you already had an alignment problem and I tell you what - if you don't get that fixed you can look at buying another set of tires a lot sooner than later. After that - you may need a tune up to get better gas mileage.

Good luck

Answer 4

You are getting worse gas mileage. If you have a GM car, pulling
to the right (slightly) is designed into the vehicle as a safety
measure. Its pulling more because your new tire has more tread
than the old meaning its diameter is greater. The old tire has a
slighthly higher rotational speed, therefore friction pulls the car to
the right. Thats why you should always replace your tires in pairs.
Also, its likely that this condition has affected you front-end align-
ment. All factors have combined to reduce your gas mileage.
To correct it, replace your front right tire with one the same size
and tread as the front left. Keep the old as a spare if it has good
tread.

Answer 5

Yes it can. Do you keep up on your maintenance, such as oil changes, spark plugs, transmission fluids, and radiator fluids? All minor maintenance can affect your gas mileage even your tires. When you replace one tire, you should also replace the opposite tire. Like both backs or both fronts. If you do this and it still pulls one way or the other, then you definitely need to have an alignment done.

Answer 6

HERE ARE SOME OF THE BEST TIPS ON HOW TO SAVE GAS:
*AVOID HARD BRAKING AND ACCELERATING
*IF DRIVING A MANUAL, SHIFT UP AS SOON AS YOU GET A CHANCE. YOU CAN SKIP SHIFTS (GO FROM 1-3-5(6) )
*INFLATE YOUR TIRES PROPERLY
*KEEP THE ENGINE TUNED
*GET A K&N AIRFILTER (GOOD FOR 1 MILLION MILES OR MORE)
*REDUCE YOUR WARM-UP TIMES. FOR MOST CARS 35 SECONDS IS ENOUGH TO GET THE ENGINE READY. DON'T IDLE FOR MINUTES. {REMEMBER: YOU ARE GETTING 0 MILES PER GALLON AT IDLE}
*CHANGE YOUR OIL REGULARLY AND USE THE BEST POSSIBLE GRADE OF OIL. VERY DENSE OIL WILL MAKE THE ENGINE WORK HARDER AND BURNS MORE GAS.
*KEEP THE INTAKE AND EXHAUST CLEAN FOR EASY AIR FLOW.

Doing the things on this list will give your engine a longer life and will take you farther with less gas.

Answer 7

You'll have to be way more specific. How many miles to a gallon or miles to a tank are you getting. Driving 6 hours doesn't mean much. You could drive 6 hours at 5 MPH and only go 30. There is not enough information here to give a reasonable answer.

Answer 8

You need to check the tread, and you might have to get your alignment checked. Other things that'll effect you mileage are driving with the windows open, running the A/C, having a roofrack, carrying extra weight, a poorly tuned engine.

Answer 9

ASK AT A REPUTABLE TIRE DEALER. IF TWAS I , I WOULD PUT THE NEW TIRE ON THE REAR AND IF YOU GET TWO NEW TIRES I'D PUT THEM ON THE FRONT. MAKE SURE YOUR GAS TANK DOESNT HAVE A LEAK. SLIDE A PIECE OF CARDBOARD UNDER THE TANK TO CHECK AND SNIFF FOR GAS SMELL. ETC. MAKE SURE THE AIR FILTER IS NEW OR VERY CLEAN. CHECK AND CHANGE OIL AND ALL THE OTHER CONSUMABLES. ASK AT DIFFERENT GARAGES ETC.

Answer 10

Get a tuneup and dont forget the air filter..... that makes a big difference. get spark plugs, oil change, air filter and dump some fuel injector cleaner in the tank.