check for exhaust leak and test oxygen sensors......

@ turbo8, I checked my rear end when I changed the front brakes. I also checked the codes, all clear. For some reason in California we get winter blend even though we don't need it, It was 70 yesterday, and its raining here and 50. I have thought about and exhaust and intake, that might help. Any suggestions to that end, brand, style, etc. Flowmaster is close to me so they can fab something up for me. Would chancing the octane improve mileage, I run 87 cause its the cheapest, would switching to 91 make a difference? Thanks for the posts.

Cheers

Bad MPG's - Things to check

Try drive 60 mph instead of 65. The more faster you drive the more gas you burn .

I agree with the above. Driving slower and not racing to red lights like everyone seems to do are the only way you will improve your gas mileage. When you start driving slower, you'll realize it really doesn't add that much time to getting from a to b.

These type of threads will never stop showing up. It sounds like your 4Runner is perfectly healthy.


If you want better than 18 MPG buy a Prius.

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Main thing you can do is stay up on maintenance. Air filters, fuel filters, tire pressure, alignment, etc.

In terms of aftermarket, I myself have added a cold air intake with a K&N cone, a throttle body space from Helix called the "Power Tower", which has these scallops that supposedly spin the air entering your plenum. Makes a pretty cool whistle sound between 1500 and 2200 RPM, almost like boost! MPG wise, if I'm on the freeway cruise control at 60 mph, I've gotten up to 23- 24 on flat ground. I drive a 2001 limited.

I also have new performance wires and brand new Densos.

If you have everything dialed, you can get that MPG up, but don't expect extraordinary gains. If you're at all aggressive, kiss those goodbye! I get about 17-18 average, minimal hossin around.

You'd swear it was a V8 by the sound after the two mods put together! Pretty inexpensive too.

Cheers

I pull 14's in the winter with 4x4 on some of the time and 20ish during summer road trips. All stock. I didn't go out and buy a 4runner for fuel economy though. The sooner you accept it the more fun you'll have driving it.

Don't be too hard on the OP as he is asking why his mileage decreased, not how to get 30 mpg.

All replies are accurate, however the OP lost 4 mpg average, and would like to know why.

In short, very hard to say specifically but some things you can eliminate by making sure basic maintenance is up to date. Air filter, plugs etc. Also resetting the ecu can help speed things up/back to their former self.

Cold can have an impact on the fuel/mileage you achieve just by virtue of the grease and oil being stiffer in colder temperatures. Winter blends of Ethanol in the gasoline can have an impact.

Also cold affects the air/fuel mixture upon start-up until the truck reaches operating temperature and runs richer. Sub-zero temperatures can play a major effect in my experiences with these trucks on gas mileage.

I have used recorded gas consumption as a tool to determine when maintenance should be done.

A few years back, while planning a 5000 km trip, I had wheel bearings re-packed and greased as part of pre-trip prep.
Monitoring gas mileage, I noticed it was down by about 4mpg and did not know why but proceeded anyways. Halfway home I had a wheel bearing overheat and seize taking out the front axle and 4wd hub in the middle of New Brunswick where parts were not readily available. Very expensive unplanned stop.

Anyhow the long and short was, one wheel bearing was put too tight during the maintenance I had done beforehand. Monitoring gas mileage told me something was wrong but not what it was. Hindsight tells me I should have rechecked the mechanics work or at least put a hand on the hubs when I noticed the increase consumption in gas.

In short, your increase in mileage could be hundreds of things.