Wrong plugs in my mini-beast

Ok, I've recently bought my first Japanese vehicle and decided to do it right by getting a 2006 Taco 4.0l 4x4. I've run 3 tanks of gas thru it with 80% highway miles getting about 14mpg. Kinda bullshit if ya ask me. I was reading the owners manual and noticed it required iridium plugs. I figured that since I pretty much assume most people are stupid, someone put standard plugs in it. Sure enough, standard plugs. See, told you most people are stupid. I'll be swapping them out friday. Here's my query, I know the wrong plugs are at least partially to blame but do you guys think that could be the whole reason for my shitty mpg?

 

Are the tires factory size? If not calculate the difference. Make sure tires are inflated to correct psi. New air filter if its old. 14 mpg is pretty low.

 

Everything is to spec. I bought it from my Dad's dealership. He's the GM. They did all the maintenance LOF, new all terrains and air filter. They never checked the plugs though. I have all their records. I'm the sales manager at Rimco so I had my tire techs check that stuff for me and it's good to go there.

 

Just wondering, but how are you calculating your mpgs?

 

I do not think your truck came standard with iridium plugs. they make a direct replacement for the 4.0. about everyone including me their trucks came with 3 ngk and 3 denso plugs from the factory for what reason who knows.do not think the plugs have anything much to do with your gas mileage. I changed my factory plugs at 94k miles with the iridium plugs and gained maybe 1/2 mpg. my truck is 2005 dbl cab 4x4 with LT 275/70/17 and ARE MX topper and I get between 19 and 20 with a mix of driving not taking in account for the larger tires. check your speedometer against a GPS, usually shows higher speed than you actually going so you are getting better mileage. take out the restrictive secondary air filter, 4 runners do not have them at least on the ones I have looked at. I would run some Seafoam thru the tank, new plugs, frontend alignment and change diff. fluid and full synthetic oil. should be good to go. also do not go with no more than load range C, better yet stick with a P metric.

 

I filled up with 17 gallons. Drove till next fill up. Put in 17 gallons and did the math. Both fill ups were to the brim so I know I actually used 17 gallons. I'm running on tank #3 right now.

Why would the manual say iridium but Toyota put in standard plugs. Just to be sure I went to the parts store and they confirmed the iridium. Yes, I know parts guys aren't geniuses.

edit: I did the secondary filter mod while I was pulling plugs. What is the service interval on those anyway? All my ford trucks said 100k.

 

In my manual it actually states that the iridium plugs are to be used with the 4 cyl only. The V6 4.0 gets the Denso and NGK plugs.

 

hmmmm interesting....off to research this a little further.

 

#1 - The 4.0 V6 uses copper plugs. Change them every 30k
The 2.7 4-banger uses Iridium... 90k change.

#2 - Copper vs Iridium will make ZERO difference in fuel economy and engine power, provided the plugs are the proper heat range and design for the engine.
Iridium simply lasts 3 times as long... and costs 3 times as much.

 

I need those, strictly because they cost more.

 

LOL!!!!!!

I need them. Strictly because I'm lazy and it's worth it to me to only have to replace them once every 3 years.

 

You got to try pretty hard to only get 14 MPG with a 2.7 no matter what plugs are in it. I would suggest the block under the pedal mod.

 

I'll be damned...Just found this...

http://www.edmunds.com/toyota/tacoma/2006/mpg.html?style=100633139&pos=9&mpy=15000

 

^^^good idea

 

I have 2006 TRD SPORT 4x4... And get 17, to 18 on last fill up`s only have 57,000 on it... But i expect to get better since the warmer weather is here

 

This is for a 2011, which I have. Its mpgs arent much different than a 2006 according to edmunds. I don't get the mpg that they are quoting. Before changing tire size I was getting 18-20mpg. After tire size change (depending on season) 16-18.


http://www.edmunds.com/toyota/tacoma/2011/mpg.html?style=101336178&mpy=15000&pos=9

 

14mpg is pretty weak for this year/engine Tacoma. Workman's 06 4.0 4x4 gets 20-23.5. Workman makes it a point to buy non ethanol fuel and always runs 91oct. Workman also runs synthetic fluid all the way around, all changed according to the maintenance schedule. Check tire pressures, that can throw it way off. If your running a heavy offroad tire, that will bring MPG down as well. Most offroad mods will drop your MPG.

Assuming that most people are stupid is a stupid way to live your life. Anyways, your owners manual is wrong, and the stupid person that put in standard plugs(as long as they are denso K20HR-U11's), is actually a very smart person. Toyota engineers designed this engine to run on these denso plugs, and they are 100% the correct heat range for the 4.0.

Stupid people spend $10 for a spark plug when it has been proven time and time again that they do nothing for performance and is some cases decrease the life of your engine. The Denso plugs are about $3.50 a piece, were designed to run in the 4.0, and have been proven to give the best performance. Yes, they have to be changed every 30,000 miles. This takes at most 2.5 hrs of your time, the amount of time that most stupid people watch TV per day.

Workman

 

Without resorting to name calling my last tank in my V6 '07 Prerunner was 21.3 mixed driving 220 highway, 40 intown with a two speed driver (accelerate or brake). Standard size 17" tires, no lift, TRD exhaust and cai. Your results may vary.

Researching products to see if they will perform up to your expectations leads to less chance of dissatisfaction.

Debating standard plugs vs iridiums is a can of worms akin to debating which oil is best. I use the iridiums because I want to and there is no scientifically proven evidence that the recommended Denso iridiums do any harm. Do you really think that Denso would sell a product that could cause them a financial loss in the product liability arena much less knowingly sully their companies reputation?

If someone wants to use the copper plugs @$3.50 each and change them at 30K it's OK. I choose to spend $60.00 to my door, check them at 90K, change if needed and use my time doing other things that I find more fulfilling than changing spark plugs.

 

I think the reason for the shitty mpg might be staring at you in the mirror... You simply chose a truck that returns low MPG. Happens every day in America...er, sorry, in 'Merica, to far too many unsuspecting folks.

Good news, though, is if you wait another 10 years, new trucks will be getting almost 35 MPG or so! Of course, gas will cost about $17.22 a gallon I'm sure, so yippee for higher MPG and we're all still screwed...

No disrespect intended here, but that's exactly what it's supposed to get (at least around town) according to the government ratings. And while Edmunds might get things wrong occasionally, the government never makes a mistake with this stuff, so here ya go...

FuelEconomy.gov - 2006 Toyota Tacoma listing

You never mentioned if this was overall MPG, city, highway and didn't state which transmission you have.

Honestly, though, it doesn't seem to matter much, though, as even at 16 mpg in the city, the "other" option with the V6 isn't exactly sipping fuel.

Seriously, though, 14 mpg does seems a bit low. If it's a big concern for you, you might consider some research on "hypermiling" to find ways to increase the MPGs, but even the best efforts won't combat the effects of driving a 2 ton brick through the atmosphere.

If I were a doctor, you were my patient, I'd prescribe a small motorcycle in the bed of that truck. It'd help in several ways:

1- MPG would decrease slightly, but the reason would be obvious
2 - you'd feel better because the truck was working instead of running around empty, mocking you with low MPGs
3 - if you rode the bike, your household spend on fuel would go down noticeably

 

I chose the truck because of it's off road and dependability reputation. Not it's mpg rating. I'll admit I didn't realize it sucked that bad. With that said, ain't no way I'm getting rid of it. I love this truck. So far it's the best 4x4 I've ever owned. You're right I forgot to mention I have a six speed but had you followed the link or read the whole page you would have seen that I chose the truck I own. Oh well, moving on.

I'll swap out the plugs to be sure they are with in the service interval and see what that does. My truck is stock except for a cat back flowmaster. I'll be upgrading other things as I go along. Wish me luck in my pursuit of bad assness