Poor Mileage on a 2004 4Runner with 45K miles

[achen]

Hello All,

Lately my 04 4runner has been getting poor mileage. Like 300 miles for a full tank when lights come on. I don't know is it because of the cold winter or age of the car. I don't know if i should change the enginer coolant even though it is good for 100,000 miles right? lifetime of the car, or change transmission fluid. I was thinking of taking it to pep boys and do a fuel injection cleaning. I don't know if it is worth the money or even work. I haven't done any MAJOR maintenance services on this truck besides the basics such as oil change, change brake pads and rotors and cabin and enginer filters. I don't know if changing the fluids will improving the mileage of the truck. I just want to know what i can do to improve the mileage of the truck.

With gas prices so high now, can I use regular fuel instead of plus? I being using octane 89 most of the time. I just switched to 87 yesterday. Would that damamge my engine by switching back and forth? Please advise. Thanks!

 

[chaz]

winter blend maybe a cause, but 87 octane is fine. if u have the pink coolant leave it in, unless u tow alot ,trans should be fine also, next time u change the oil use synthetic, maybe cleaning the MAF sensor & use of seafoam or injector cleaner will help, after that u can try resetting the ecu & see if theres any improvement.save some $, its easy to do urself

 

[LEO98]

My MPH has fluctuated lately as well, possibly due to my recent DS 2.5/1.5 lift. My computer shows 380 miles on a full tank-4WD 2007 V6. My 2003 would show 400, yet it was a 2WD.

Being in WEST Texas, for some reason we get 86 and 88 octane. I get between 17 to 19 mpg on average city driving. When I travel to south Texas, where 87 is more prevalent, I average 18 to 22, sometimes getting up to 23 and 24 mpg.

Must be the octane and difference in elevation. I typically use 86 octane, unless I run across a station with 87, or at least it says it's 87.

 

[Carl_G]

I didn't realize 300 miles per tank was low.

I have the 2003 v8 and with mostly city driving I get about 305 to 310 miles per tank.

 

[achen]

Chaz,

What does it benefit switching to synethic oil? Any reasons and benefits besides costing more than regular oil? Also how do you reset the ecu? You think i should do a complete fuel injection cleaning system at pep boys? you think it's worth the money? I never done a fuel injection cleaning before.
you think i should flush the steering wheel fluid and brake fluid? is it necessary? I beilieved i cleaned the MAF sensor like 2 months back. I took it off and cleaned it. it didn't do much in terms of mileage.

 

[BigPig]

My MPH has fluctuated lately as well, possibly due to my recent DS 2.5/1.5 lift. My computer shows 380 miles on a full tank-4WD 2007 V6. My 2003 would show 400, yet it was a 2WD.

Being in WEST Texas, for some reason we get 86 and 88 octane. I get between 17 to 19 mpg on average city driving. When I travel to south Texas, where 87 is more prevalent, I average 18 to 22, sometimes getting up to 23 and 24 mpg.

Must be the octane and difference in elevation. I typically use 86 octane, unless I run across a station with 87, or at least it says it's 87.

Several of the 7-11s around here (Lubbock) have 87 for the low grade but mid is still 88. I'm only averaging about 16 mpg but I have a short commute and spend a lot of time sitting in traffic due to construction.

 

[Merle]

Cold weather and winter blend will hit you. I notice a massive drop in MPG depending on the season, my average speed, and where I fill up.

CA w/ ethanol during winter will get me 305 MPG. Nevada w/ non-ethanol during spring/fall will get me 400 MPG.

 

[Jeff4runner]

Chaz,

What does it benefit switching to synethic oil? Any reasons and benefits besides costing more than regular oil? Also how do you reset the ecu? You think i should do a complete fuel injection cleaning system at pep boys? you think it's worth the money? I never done a fuel injection cleaning before.
you think i should flush the steering wheel fluid and brake fluid? is it necessary? I beilieved i cleaned the MAF sensor like 2 months back. I took it off and cleaned it. it didn't do much in terms of mileage.

Synthetic oil is alot longer lasting, and wont break down as easy. It also retains its lubricity to specs better than conventional. Your car is not close to high mileage, but its way past break in, so syn. will be a nice treat for the engine.
As for the ECU, just disconnect the battery, and let it sit for a few minutes. You will lose preset radio stations, and a few other things in the radio memory (JBL or not), but thats not a problem.
If you take it to a shop to do a "fuel injector cleaning," they honestly just seafoam the car. If you arent comfortable pouring liquid into the engine (extremely dangerous if not done very slowly), just pick up a can of seafoam that you can spray into the intake manifold. This is 100x safer, and wont hydrolock the engine. If you want to do that, there is a small vacuum tab on the drivers side of the intake that you can use (will send pics/details if interested). If all else, you can take it to a shop to do, but its just a money maker for them. Beware though, seafoam may foul up your spark plugs, so dont do it too much.
Finally, dont even worry about the PS fluid. As for brake fluid, it wont do anything to mileage, but you will have stronger brake response, and a higher boiling temp under load, which is a very good thing. Brake fluid flushing is just a nice little extra that may save some money.

Sorry I hi-jacked the response, but thought Id throw in my 2¢. Do this stuff all the time in shop.

 

[03_4x4Runner]

Clean your mass air sensor and run a good fuel injector cleaner in a tank of gas.

 

[Lineman]

Are you running an Ethanol blend 10-20%? Try getting Ethanol free gas. That should help you


Ethanol-free gas stations in the U.S. and Canada