Drop in mileage....

Hey all.
I have been pretty diligent in checking my mileage when I fill up, and there's been a sizable drop over a relatively short period of time.
My average was low 16 for Highway and City Street combined, or 17 if I was doing a lot of freeway driving.
The results for the last couple-three tankfuls has been 14 !
That seems a bit drastic to me
No check engine lights.
Fluids all seem to be good.
No apparent change in idle or shifting speed Etc.
Anyway...
Any input is much appreciated.

 

As a new owner since mid-December, I noticed similar changes, but based on the temperature and humidity. I mainly run run it 20 miles to work and back, with 19 of them on the highway. Not pushing it, 66-68 mph on cruise control. The higher the temperature and drier the air, the better the mileage.

 

Question, is the 14mpg coming from the read out out, or are you doing the math when you fill up at the pump? (Miles driven per the trip odometer divided by the gallons used to fill up the tank)

 

Very cool

 

I'm not sure about any readout.
My O2 is an SR5 not very high-tech.
The stereo has a cassette deck.
Anyway yeah, I am doing the math at fill up.
And it's literally only been the last couple three fill-ups that it's been so drastic.

 

Some things that come to mind.
Check the condition of brake pads/shoes to makes sure they're not binding
Does the AC clutch disengage when not using it?
Check the OBD making sure that there are no codes
How about the condition of the air filter? When was the last time that plugs were changed?
Have you changed where you purchase your fuel from?

 

Plugs and filter are good, I'll definitely check for codes.
I'm kind of all over the place on gas.

 

Wait for the air to drop?

 

Or E20 maybe?

 

You're talking about a 2002 SR5?

Really could be anything on a 22 year old truck. Is it throwing any codes?

 

An easy, low cost thing to try is cleaning the MAF sensor.

https://www.youtube.com/watch?v=xVoNOuSLYTM&t=235s

 

Checking that next

 

I did that not too long ago but I still have half the can left so I might just do it again

 

Check tire pressure

 

March winds.
At least around my neck of the woods.

 

It's Breezy here too

 

Well, I had to do the chalk test because of the whole SR5 versus limited disparity for the door jamb specs on pressure, it's quite a bit lower than what's on the jamb or the tire..
but it's what I need for even wear.
it couldn't hurt to check it again though

 

Winter gas usually drops me about 2 mpgs, other than that, I had a dramatic improvement in mpgs after changing the inline fuel filter, so if that’s never been done I’d suggest it. Cheap part easy job.

$46 Toyota Fuel Filter - 23300-62030

https://www.amazon.com/Genuine-Toyo...5------------&vehicleName=2000+Toyota+4Runner

 

Definitely on my to do list!