Huge decrease in MPGs. What the...

[ShawnD1]

You're not using snows are you? They get lower fuel economy than all-seasons.

There's almost no difference. I put my winters on in early October and I was getting pretty close to the same mileage. When the snow fell, gas mileage dropped by at least 20%. Snow is horrible for gas mileage.

 

[TridenT]

Did you check them cold? The tire pressure ratings are for when the tires are cold. If you drove somewhere to check you need to add another 2-3 psi. Usually 34 in the front and 32 in the rear works well for most.


Also fuel filter, PCV valve, lazy O2 sensor, dirty MAF, etc...

What milage and year?

Like I said, they're perfect. I've checked them cold. It's not the tires. I'd know if it was the tires.

Fuel filter is less than a year old. I really doubt it. The rest, IDK. Those are kinda hard to test for and expensive to replace.

129k, 2000.

This only happened in the last 1,000 miles. Something is weird. I'll see what I get for this tank. Who knows. :/

Like I said, the last two normal tanks have been significantly lower. (22-23mpg) The other almost all freeway tank was 32mpg. Idk why it's like this.

Regular tires...

 

[Viperoni]

Best bet is going to be looking at a scanner that can show fuel trims, idle counts, coolant temp, o2 output, manifold pressure, air flow, etc. And if you have an auto make sure the fluid/filter are maintained and converter lockup is functioning. Other things I haven't mentioned like maladjusted parking brake will show up as abnormal engine load on the scanner.

and

Also fuel filter, PCV valve, lazy O2 sensor, dirty MAF, etc...



Best advice in the thread.
When's the last any of the latter have been changed?

 

[alevasseur14]

There's almost no difference. I put my winters on in early October and I was getting pretty close to the same mileage. When the snow fell, gas mileage dropped by at least 20%. Snow is horrible for gas mileage.

Same. I put my Blizzaks on about a month ago and have only dropped 2-3 MPG. That could be anything from winter formulations to colder ambient temperatures. These are my first winter tires and they are AWESOME. I'll gladly trade 2-3 MPG for superior performance.

 

[TridenT]

Wow. Huge drop again. I got around 20-21mpg this time.

WTF

It's been almost all city driving and not very long trips (Usually less than 5 miles before stopping). But come on, my car is a Honda Civic... 🙁

 

[PhoKingGuy]

Wow. Huge drop again. I got around 20-21mpg this time.

WTF

It's been almost all city driving and not very long trips (Usually less than 5 miles before stopping). But come on, my car is a Honda Civic... 🙁

Short trips with a cold engine kills your fuel economy.

 

[thescreensavers]

Any ways to figure it out? Maybe my fuel injectors are fucked or what?

You can try Redline-Si 1 you can get it at pepboys its 8 bucks, use the whole bottle at once(shock dose), The proper ratio is the whole bottle for 20 gallons, so just use a bit less since yours is like 14?

 

[mHubs]

Short trips with a cold engine kills your fuel economy.

Indeed. I got 18mpg in my Subaru last winter because most trips were less than 5-6 miles. This winter I've got a lot more highway miles and I'm getting 23-24.