Crappy gas mileage

I recently purchased a 2001 sr5 with the 3.4L v6 in it for the 4wd in the Wisconsin winters, and the better gas mileage out of the v6, or so I thought! I purchased the vehicle with 300k on it (yeah it has seriously high mileage, I know!) for $2500 but these engines with the proper maintenance can run forever, the Carfax shows an impeccable maintenance history from the same Toyota dealership since it was purchased new. I am only the 3rd owner, the body and undercarriage are rust free, very clean inside and out, and hell, it came with about $1500 of rims and brand new tires on it. Everything was in fine working order so I jumped on it. It runs great with no noticeable misfires and it idles fine. My research led me to believe that I was going to be getting about 19mpg give or take a few (apparently 19mpg is what they got when they were new) but I am only getting about 14mpg and I don't know exactly why!? Could the engine just be getting tired?! I plan to stick some serious dough into the engine to make it more fuel efficient. My plan? Do all the usuals first, plugs, wires, fuel filter, and air filter and a tune up. Is there something else that I should do before I do those things? What are some other things I can do to my truck to improve it's fuel efficiency and give me the biggest bang for my bucks. Engine diagnostics? Timing adjustment? I have a pretty good budget to throw at it considering it's paid for already! Any thoughts on injector cleaners, fuel additives, seafoam? Any and all suggestions considered and are much appreciated.

Also I am trying to find chrome accessories for the exterior of the truck that are reasonably priced (brush guard, step tubes, and those cool tail light guards) I can't find any of the tail light guards in chrome anywhere!!

 

Welcome! Nice truck.
Winter gas + aggressive AT tires =14mpg. You'll probably do a little better come summertime
Until then, stay off the skinny pedal if you're concerned about MPGs

 

Will using the cruise control affect the mog? First 4wd ever for me! Speaking of 4wd in the Carfax report I couldn't find anything specific about the differential fluids or transfer case being done! Is it recommended those fluids be changed? Should I just do it anyways just to be safe? Er no?

 

Yes change them now if you do not know about them being done. Personally at that kind of mileage I'd change all the fluids but that's just me. Power steering, brake, transmission, coolant, etc. Unless of course you have definite records of them being done regularly.

 

if the engine sounds like it's running fine, it's probably running fine. you might want to get it checked out to make sure it's not delivering too much fuel (running rich), or that it's not throwing any codes, but if you're getting poor gas mileage it's probably you, not the vehicle.

 

17MPG is about normal for this rig. 19 was wishful thinking when new. Make sure you only use TOYOTA ignition components.

Your Throttle body is probably going to have issues at some point.

2001/2002 TBs are not serviceable and I was getting poor mileage before driveability took a hit. I think the TPS side was bad but Toyota doesn't sell anything but the complete Throttle Body. (discount Toyota Dealers will sell the whole unit for $625).

Clean your MAF and change the air filter. Can't hurt.

 

Toffees, I'm not drinking the gas if that's what you are insinuating! Due to where I live all my miles are highway miles. I am not a gearhead when I drive my 4runner I have a 2011 Charger for that. I accelerate evenly up to speed and engage the cruise control at 70 and I am done. So no, I don't believe it's me, but thanks for the comment.

 

Nothing personal meant by that, just that everyone gets different mileage, and if you stacked up all the 4Rs against all the 4R drivers, what matters most in mpg = build (weight and drag), circumstances (where you drive and what the commute is like), and driver. The actual machine differences are small, unless you've got something causing it to run rich.

My wife's van gets tremendous mileage, but when we stuck a box on it and loaded it up with x000s of lbs in people and cargo, mpg dropped to under 18 for highway driving at 75+. Go figure.

 

Non taken, I am just looking for anything I can do from a mechanical standpoint that may increase the mpg.

 

At least you saved $ on the rig. Sweet price for that ride.

 

make sure it's not running rich
reduce weight and drag
reduce rolling weight (heavy e-rated tires will kill)
if it's lifted, that adds drag, and if the suspension is too "soft" that can eat up power also

 

Thanks I really love the body style of the gen3's! I was looking for like 2 months for this type of vehicle on all of the"major car finding" apps. Completely frustrating experience! My friend looked for 15 minutes on Craigslist and found this truck, go figure! I absolutely love it!!

 

It gets what it gets everything mentioned will deliver minimal results in my opinion. 300,000 is a lot of miles I don't care what the vehicle is and that's a huge factor also.

 

So what do you recommend for achieving more significant results?

 

Also...just cleaning the TB is a good thing. The problem is that for the 2001-2002 4Runners they used a drive by wire setup. If I have it right, there is a pedal position sensor that is attached to your gas pedal that the computer then uses to electronically adjust an electric motor in the TB. Then the CPU uses the TPS to see if the adjustment it made is all good. If any of that is out of spec...things don't run well.

When I replaced my 250k miles TB with a brand new one, this is what was fixed:

Eliminated throttle delay. Improved response.
Smoother/Predictable shifting of the transmission.
Much Reduced pinging of the engine on cold days.
Smoother acceleration.
TPS engine codes.
IAC engine codes.
Mileage.
Low Idle.
Surging when AC kicks on.

My plugs/wires went to 200k miles before I was getting hesitation. Replaced those with OEM ones.

I've had the car since new and I can honestly say that now she runs like I've always remembered her running.

 

Any certain type of cleaner that you would recommend for this project?

 

CRC Throttle Body Cleaner

 

Thanks much for your recommendation!

 

Try driving 60mph or slower for a tank of gas. See if it changes.

I'll bet you go up to 16mpg, which is completely reasonable with those tires.

 

Are the tires on my truck really considered aggressive tread ?

 

They're more aggressive than stock. More importantly, they're heavier.

 

Thanks for your information! It gives me a reason to buy a set of summer rims and tires! What type of tires do you recommend for a second set that would still give me adequate grip if I were to take my truck off road? Just trail driving I'm not a big off roader.

 

Before you run out and buy new tires, I would honestly try driving slower on the highway to see if you bump up your mpgs. That will tell you if your problem is just a heavy foot.

The BFG A/T's are a great all around tire, but if you run out to buy new tires to save on mpgs, you'll be spending $1000 for 2mpg. It'll take you quite a while to get that back in savings.

If you're dead set on new tires for mostly street/light trail driving, check out Michelin Defender LTX M/S's. Fantastic tire that will last you forever. Also check out a Firestone Destination A/T2 in a P rating. It's a mild A/T tire that is one of the lightest on the market.

 

I really baby my truck just because of the high mileage. I accelerate evenly when I get on the highway and when I reach my speed I engage my cruise control. Could that be the problem?

 

I don't think so.

Our trucks are obviously not very aerodynamic. The faster you go, the more air you're pushing and the quicker your mpg's drop off.

I used to get 16mpg very consistently in my 5th gen going 70-80mph on the highway. Then I moved to an area where the highway speed limit is 55mph and my mpgs instantly went up to 18mpgs. This is with 285 sized tires as well. If I had the stock tires, I'd probably get another 1mpg out of it.

You're probably loosing a little mpgs with your tires and some more with higher speeds on the highway. That's why I think you could probably gain a couple more mpgs going slower on the highway.

Remember, when they print the mpgs for new cars, they're not basing it off going 75mph on the highway with a headwind. It's going more like 55mph in a brand new vehicle with stock tires on a dyno with no wind. 19mpgs for your vehicle is fairly unrealstic in real world conditions in the first place. I'm sure some people will claim it, but it's not what the average 3rd gen driver is getting.

 

Thank you very much for your information and time. Very insightful..

 

This is a huge factor. Someone better with the numbers (or who knows the formula) can maybe give you specifics, but rolling weight/unsprung weight is different from sprung weight (above the suspension/truck load). I'm running Cooper P-rated AT tires--not durable enough for rock crawling but more than decent tires for most stuff--and these are 42 lbs each. The BFG C-rated tires are about 45 each. The E-rated BFGs are north of 53 lbs each. Tread patterns matter but weight is probably the biggest factor for tires.

 

That's some serious information there! I should just take it in, make sure that it's dialed in, all systems running within specs and the rest is as they say...it is what it is!

 

I just got a set of the Firestone Destination A/T2s about 5k miles ago. I love them. Pretty sure mine have a T rating. They nice and smooth and no extra noise that I noticed.

 

Oh, it's way way worse. The car companies game the system as much as they can to try and walk a line that on one side woos customers with good numbers and on the other might piss them off when they can't get those numbers in the real world.

https://www.edmunds.com/fuel-economy/heres-why-real-world-mpg-doesnt-match-epa-ratings.html