Terrible gas mileage 3.4l v6. Don't know cause!

So I have 2002 tacoma v6 trd package and for about the past 2 months I have been getting in the range of 11 to 12 mpg. I do want to say I live in northern minnesota, we have bad roads. In the winter so I have 600 lbs of sand bags in the bed and about 150 lbs in the toolbox. I also have some aggressive tires but considering the fact that the last 2 winter before this I have has the exact same weight and tires and was getting about 16 mpg. My tie rods are bad but could they really effect my mpg that much? I have no check engine light, have replaced all belts, rotated tires and balanced. New spark plugs about 15000 ago so they shouldn't be bad yet?! I don't know what else if left. Any ideas please say!

 

Clean the throttle body.

 

Would that effect it that much? I forgot to mention I don't have any power lost or anything like that.

 

It's a simple solution for what may or not be a problem.

 

That's true. I will do that and see what happens. Any other ideas from people would be great. Thanks for the ideas

 

Dirty air filter can cause mpg to go down plugged cat convertor but that should throw a code.

 

I forgot to mention I changed air filter. I am just lost on what it could be. I was thinking maybe a cracked fuel line?

 

get rid of some dam sand bags mang!

600 lbs is lot. I carry 2 70# bags and that's it

It all has to do with where/how/when you travel. Realizing this has been one of the longest and coldest winters in a while would also cause your mpg to drop (I've noticed mine too) due to the extended warm-up time, denser air causing the AFR to use more to burn, etc, etc...

 

I get about 12 mpg (city) with the same vehicle. I blame the winter fuel. I don't let the truck idle for more than 30 seconds... even when it is 0F outside. During the summer, driving the same way, I get about 18 mpg.

As another person said, clean the throttle body and check/replace the air filter. Those are the only two simple solutions I can think of without diving in deep (unless if you are heavier on the throttle, of course).

 

Ya i know 600 is alot but that way I never have to worry and gets me some more traction to help pull people out.

 

I was getting a consistent 12.5 mpg. I changed the pcv valve and differential oil and increased to 15-16 city.

 

If you are doing short trips, with the sub zero weather you have been enjoyng where you are, this is normal.
I also have a Subaru that gets 24-28 in the summer, but it is down to 18 in this
cold.

 

How old is the fuel filter, pcv valve, and upstream A/F sensor?

 

Winter fuel is different than summer fuel and has an impact on mileage. Check your PCV and diff fluids. Also do a smoke test and check for a vacuum leak.

 

Fuel filter has about 10000 on it. They last longer than that right? Pcv valve is unknown so I will check that out and same for the upstream a/f sensor. I'm taking my truck in this coming Monday and going to have them check everything out. Thanks for all the help. I will get back to you on what was wrong.

 

Do u have 4x4? That would eliminate the need for 600 pounds sand bags I think.

 

I haven't changed my fuel filter ever and still get around 15-16 with 33s, skids, toolbox, bumper. OP, check spark plugs, use some fuel injector cleaner every oil change, and stay on top of your air filter.

 

I replaced my fuel filter, gear/diff oil, reg oil to synth, and air filter at 110k

noticed no changes in mileage and that was back in October. the reg oil and filter were always changed regularly but other than that nothing else was needed before (never had issues). checked PCV and it was fine so I left it alone per maintenance (if it still has vacuum there is no real need to replace it).

the only thing I may need to do when it warms a bit is to recheck my cleaning of the TB. having rougher idle and lower rpms than usual at times, even after warm-up. I may need to pull it off an give a thorough cleaning along with the IAC to make sure it's not clogged.

 

From what I have read the pcv valve is usually about 100k. It says to replace at that. I am about 100% certain it has not been replaced but I may be wrong. I am just going to have the shop replace all fluids, pcv valve, check fuel injectors, check my brakes. Anything else you guys can think of that I should have them check? I do want to mention that the more I think about it my spark plugs have about 30k on them but they are the new e3 plugs. I was told you could run 40 to 50 on them but I could be wrong? Any help would be great guys

 

Well it would at times but when I do put it in 4x4 and with the Weight in the back it helps get the back tires some more traction. I know it sounds extreme but it has saved my butt a quite a few times so I just stick with it