Poor gas mileage

What can cause my gas mileage to drop, after changing the plugs? I went from 17 mpg, to 14 mpg. At todays gas prices, every little bit helps! Everyone tells the fuel filter is not normally the problem. I did notice recently that the hose going to the evap was off, I put a clamp on it, the a few days later, the hose next to it had come off. I clamped both of them. Any suggestions?

 

I get between 14 and 17 MPG, depending on driving conditions, usually about 16 MPG, always, since new. I doubt it was because of the plug change. 14 MPG is within reason for these gas hogs. Perhaps just driving conditions. Carefully monitor it over the next few fill ups and see if the mileage goes up to what you're used to seeing.

 

14! Count your blessings! I get 9!

 

I’ll nestle in between at 10.5-9

 

Have you changed how or where you’re driving recently? Doubtful it’d be from the plugs, but what plugs did you put in?
I’m consistently averaging 13.5 where I live, low speed, lots of hills, sometimes towing a double axle trailer. If I throw just a bit of highway in the mix (like 1/4 tank maybe) my average goes closer to 16.
I’m basically all stock at around 350k km on it and drive it the best I can for economy.
$165 to fill up with regular the other day…

 

Check for vacuum leaks, clean your MAF sensor, make sure your O2 sensors are metering well (voltage wise)and maybe clean your injectors? Change the plugs and try using OEM. Basically check anything that would cause you to run rich.

I do remember in the past people complaining about poor gas mileage using non-OEM plugs. Just a thought.

 

It got warmer where I live recently. Check tire pressure.

 

I'd love to get 14....never seen better than 13....usually 10-12

 

I get 12-13 city, 15-16 if all hwy.

But beside that, which spark plugs did you use? With my '06, pretty sure Denso iridium plugs are required.

I could definitely see using the wrong plugs causing a drop like that.

 

I get smiles/gallon when I drive mine. Honestly, never bothered figuring the mpg I get with it. Its not great I know, because I like the sound of that Flowmaster.

OP, give your truck that going downhill stance like this feller and then just coast everywhere. Should improve your em pee gees. LOL. Just remember to drop the tailgate so the air can escape from the bed for that ultimate efficiencies.

 

Check to make sure you didn't get the wrong plug, a set of Chinese knock-offs or damage one when installing. Your loose hoses could also be your problem.

Don't buy gimmick plugs. Use only the exact plug recommended by Toyota and don't buy them from ebay.

 

Also don't buy from scAmazon. Same problem with knockoffs. Neither fleaBay nor Amazon have any way to prevent counterfeit and/or grey market items from entering their inventory cycle and/or being posted at their site. There have been too many cases of counterfeit product being bought there in the past for us to count.

 

This is important. I almost destroyed our RAV4 engine with counterfeit Denso spark plugs.

https://www.tundras.com/threads/counterfeit-denso-spark-plugs.64225/

 

We're getting a bit hung up on comparing our own mpg against the posters. That's practically apples to oranges.

@billychad if you're still here (we get a good amount of one post wonders) how did you come up with your mpg numbers? How long have you tracked to come up with the 17mpg?

About these evap hoses, how did you notice those? You mentioned you clamped them, do you mean you connected them to their respective bugs and clamped them on? If not, you may still be seeing winter fuel and there is a chance it is evaporating faster if there has essentially been an open vent coming off your gas tank.

 

According to Toyota in 2001. My original window sticker expected MPG ratings.

 

I took my steps off, im a shoe-in for the 18mpg club when i air my tires up hard. And i’m 4wd.

 

“33s” but I do 99% city short trip driving

 

Super skinny lightweight tires with little to no rolling resistance might help those MPGs. Not so much for braking capability though.