Mpg getting worse

Anyone know what’s up ? So I’ve been getting 11mpg on the highway 2rz 2.4 which is horrible , I’ve got no check engine lights , i replaced the post cat o2 sensor a year ago , I do have bigger tires but I’ve had them for about 2 years (mpg is horrible now )

 

I looked around and found a TacomaWorld thread with a link for an FJ owner who did an amazing write up. He traced his mpg issues to his thermostat...

https://www.tacomaworld.com/threads/sudden-drop-in-mpg.314485/

OR

http://www.fjcruiserforums.com/forums/engine-performance/119773-fuel-mileage.html

Normal advice around here seems to be:
Clean MAF, clean throttle body, change plugs and wires, clean or replace air filer, and maybe fuel filter....

 

did you check for exhaust leaks? Mine was leaking at every connection from the bolts on the manifold all the way down. tightened em up and my mpg got way better. Run some sea foam through the vaccum lines on a cold day and see if any smokes comes out of any where besides the tail pipe.

 

It may seem simple but I had the same problem and just cleaned the air flow sensor, mpg was immediately back up to 19 around town an 23+ on highway. I think it was the k&n drop in filter oil to be honest (Even though I was careful not to soak it) so I switched back to the paper filter.

 

K&N oil filters are the best!

At making more noise!

It's all marketing wank, the only way to flow more air is to either have greater surface area for that air to pass through, or make the pores smaller, and that's exactly what K&N did. If you hold up a K&N filter to the light you can see there's all kinds of needle sized holes directly through the cotton mesh, the way K&N is supposed to filter is using electrostatic attraction provided by the oil and the air moving through it generating a slight negative charge, but it's not really effective, does it add more power perhaps, but nothing that will ever be noticed.

However

The oil *WILL* wick off the cotton media and burn and carbonize on the MAF fine hot wire and kill your MPG.

But K&N says the baja racers run the filters!

True but the Baja race teams can afford to replace their engines after every time they play in the dirt.

Can you?

Don't fall for the wank, use a OE style dry filter.

That said I do use a K&N filter in my truck.

The cabin filter.

If you want more filter area/more air with a dry filter you could always do my FJ intake airbox mod!

 

I had a K&N in my old Mustang. It did add power, but I eventually swapped it out for a regular dry replacement. The power went down a little, but I definitely saw a rise in MPG.