Bad Mileage

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fossten

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I've noticed my mileage dropping significantly lately. I cleaned my K&N filter but no change. I'm getting around 15 mpg. Any ideas where I should look first?
 
and keep your foot off the floor, when it rainy and roads are wet I am sliding around every cornerm and when I get the feeling to play I only get 15-16 but I run Abe hard
 
Chevy Volt goes 40 miles without gasoline! Consider it! LOL, just kidding dude.

If mileage dropped off suddenly like that I would suspect something isn't working right.

What about a tire or two that are super low on air because nails are stuck in them?
Stuck brake caliper?
Stuck parking brake?
I've even suffered from a leaking gas tank before.

Any noticeable changes in drivability that might point to the cause? No C.E. lights I'm assuming?
 
brentalan said:
Chevy Volt goes 40 miles without gasoline! Consider it! LOL, just kidding dude.

If mileage dropped off suddenly like that I would suspect something isn't working right.

What about a tire or two that are super low on air because nails are stuck in them?
Stuck brake caliper?
Stuck parking brake?
I've even suffered from a leaking gas tank before.

Any noticeable changes in drivability that might point to the cause? No C.E. lights I'm assuming?
Click to expand...
LOL good one Brent...

Actually you just hit the nail on the head - I just replaced my pads and the car is pulling to the right when I brake - I bet it's stuck. I'm pulling the rotors this weekend anyway - I'll grease the calipers really good. I'll also check the MAF sensor.
 
When you drive it, if there is a real issue with the brakes sticking the wheel(s) in question tend to get very hot.
 
Ya, take the car for a drive and use the brakes as little as possible, then stop the car and feel the wheel with your hand, see if there is a big temperature difference.
 
It could also be the 10 percent of ethanol the feds are allowing into our gas. :shifty:
 
man i got 33 mpg from denton to mainsfield with the cruise set to 65mph me and my buddy were down to 2 smokes and $5 he was amazed. but i average 17 mpg in town
 
Ethanol will hurt gas mileage but it's been in the gas for some time now so a new decrease couldn't be attributable to that.

Ethanol is 10% of the gas and there is a 20% hit on that 10%. That works out to a 2% decrease; so even if he did have 100% gas and moved to 90/10 gas/ethanol that works out to less than half an MPG on a car that previously got 20 mpg. He said the change in mileage is significant.
 
Heres a tip for ya on brakes, spin the wheel, if there's resistance, something is binding..

Now you've got 4 things it could be

1) binding caliper
2) flapper valve in hose holding pressure
3) binding brake hardware
4) bad bearing

To check the caliper vs hose simply open the bleeder valve, if the wheel frees up, then you know you have a bad hose
 
No resistance in the wheels spinning, and I checked the calipers, they're all still greasy and moving fine. Next will be the MAF sensor. Front tires are a bit low so I'll check them too.

By the way, I used my new Kawasaki electric impact wrench to take the wheels off. It had to try a few times for a couple of the hard lug nuts, but it gets them off, no muss, no fuss. Not bad for $75 and it saves me a lot of backaches. I'm getting modernized finally...
 
Have you done the maintenance?
Plugs, wires, fuel filter? Even tire pressure. That's a decent starting point.

Is there any rougness with the idle? A miss? or a lag or hesitation underload when accelerating? Because vacuum leaks are the next big problem. The leaking IMRC bearing on mine hurt my city driving fuel economy, but seemingly had no impact on the highway mileage.
 
Calabrio said:
Have you done the maintenance?
Plugs, wires, fuel filter? Even tire pressure. That's a decent starting point.

Is there any rougness with the idle? A miss? or a lag or hesitation underload when accelerating? Because vacuum leaks are the next big problem. The leaking IMRC bearing on mine hurt my city driving fuel economy, but seemingly had no impact on the highway mileage.
Click to expand...
Plugs and wires have been done recently. Fuel filter - not recently - I changed that when I did the coils several years ago. Tire pressure - pending - but would that affect it by 25%?

Idle is fine and accel is fine. Highway mileage has been hurt too.

I used to notice a gas smell when I'd get into the car after it was parked overnight - but that's gone now.
 
i doubt fuel mileage would suffer with a clogged fuel filter, performance would suffer ,but not mpg's
 
Soooo wrong, if your performance is suffering the MPG's will also suffer it goes hand in hand. My Mark 8 picked up 4 MPG's from a 10.00 fuel filter. When i bought my V6 Firebird it had 142xxx miles on the stock fuel filter and was pulling in 10 MPG, with just the fuel filter change it jumped to over 24 MPG. Fuel filters should be changed about every 10,000-15,000 miles
 
Fossten where do you drive the most at??? When i drive on the Watterson and the surrounding areas i get the worst MPG's ever. Driving around in Shepherdsville i only get 18 MPG's but when School gets back in and i drive from Elizabethtown to Shepherdsville everyday i get 25-28 MPG's. City driving in Louisville will kill any car!!
 
The connector on the bottom of my fuel filter failed when I was at about 190k mi.
Gas mileage fell a little bit and I could smell gasoline after I'd finish my hour drive.
Eventually, I saw a little, tiny, puddle of gas under the back of the front passenger wheel.

I initially just thought maybe the filter was clogged. I replaced the filter, disturbing the tenuous seal that had previously existed and upon start up, gas started pouring out.

Easy fix.
NAPA part, right off the shelf. Removed the fuel line hose until your back to the metal, heat the new one, slip it, on, and you're on your way.
 
jrherald420 said:
Fossten where do you drive the most at??? When i drive on the Watterson and the surrounding areas i get the worst MPG's ever. Driving around in Shepherdsville i only get 18 MPG's but when School gets back in and i drive from Elizabethtown to Shepherdsville everyday i get 25-28 MPG's. City driving in Louisville will kill any car!!
Click to expand...
Yeah I drive the Watterson, but I still usually average b/t 19-21 in the city. Now I'm down below 15.

A buddy of mine thinks maybe there is unequal pressure in the brakes and told me to compress both calipers simultaneously before reinstalling them. I might try that too.

Cal, I'll check out the fuel filter. Thanks.
 
There's a vacuum leak somewhere. You need to have it smoked to see where it is leaking from. Could be the egr, IAC, intake, no telling. Right now you are grasping at straws.
 
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