It seems since I put the new head gaskets on my 3VZE it gets very bad fuel mileage. I had the injectors serviced by SuthBay Fuel Injectors, put LC Engineering Headers and complete 2.25 exhaust on, made double sure I have no vacuum leaks and I don’t have any engine codes but I get about 13 MPG. I do run 35” Maxxis Bighorn tires but my last 4Runner with 35” BFG MT’s got about 18 MPG. By comparison, my neighbor across the street just did the head gaskets on his 3VZE, had the fuel injectors serviced (at SouthBay), but put the stock exhaust back on and gets about 19 MPG (he runs 33” Pro Comp AT’s). I figured with opening up the exhaust I’d get at least the same or better MPG than my neighbor does, any ideas?

 

What gearset do you have in your diff?

Did you put the O2 sensor back in or running without it? A bad or missing O2 sensor will send your mileage to the toilet.

Also, are you correcting for the large tires when you check mileage? (is your speedo/odo correct)?

 

If the gears are still factory and I’m reading the axle code correct, I’m running 4:56.

I didn’t replace the O2 sensor but I figured if it was bad, it would throw a code. I’ll go get a new one.

I’m using a GPS for my spedo and mileage figures. I was going to use a spedo calibrator but realized it was mechanical so that idea went out the window.

 

4:56 should give you TONS of torque with 31" tires.

Let us know what the O2 sensor does.

 

Subscribed - After a valve job, head gaskets, fuel injector service (Witch Hunter), headers and 2.25" exhaust installation, my city mileage dropped from 18 down to 16. I am running the stock p225/75/15 size Kumho AT's with 4.30 gears. Previously I ran Michelin LTX's in the same size, so I assume the reduction in mileage results from swapping to an AT tire.

My truck runs great though, perhaps the awesome rumble when I press on the skinny pedal has something to do with it