Low MPG's with my 3.4L

I've seen in Facebook groups of people getting way better MPG's than what I've been getting with my 3.4L. I get about 9 - 11 mpg on the street in my city and about 14 - 17 on the highway.
The motor is a rebuild with only about 30k miles on it and the truck is pretty much stock with a 2.5" lift front and back with the stock size 31's. It does have a Yakima roof rack I don't drive fast and I'm easy on the pedal.
It also doesn't seem to have the towing power that it did when I got the truck 16 years ago.
I was able to pull my 2k lb. popup trailer while hauling 2 dirt bikes up grades without a problem. Now, when I pull my utility trailer with camping gear, r probably about just over 1k lbs. total with a kayak on the trailer, sometimes I need to drop it down to 2nd gear to maintain 55 uphill depending on the steepness of the grade. I've seen posts of people pulling heavier trailers without problems.
What maintenance can I do to see if it helps?

 

What if any other vehicle do you drive ?

When did you notice the drop in performance ?? When was your Auto Trans last serviced?

You keep after the normal maintenance? Air Filter plugs wires ?

When was the last time the throttle body was cleaned?

Your mileage is about the same as mine my best highway mpg was ever only about 15mpg

 

Gap your spark plugs, clean your MAF, make sure cat isn't clogged, run a fuel injector cleaner... The works

 

I don't know if your crank pulley is set up the same as my 22R-E but that was my problem. The pulleys slipped on the rubber of the harmonic dampener and when I set my timing, it was off by 20 degrees or more since the timing mark is on the pulleys. I checked the position of the piston in relation to TDC on the pulley and they did not agree at all.

Joshua

 

After cleaning and checking live data on the maf sensor....

I would check egr valve system first....

I would hook up a scanner and run live data on the egr valve....make sure its switching on and off when its supposed to...
it could be stuck open or closed....watch the fuel trims while in this process.....

Not sure if cheap scanners will give you access to the egr valve....dont think my blue driver one will do it....unless they updated the firmware recently....

I have to use a thinkscan one to see mine

 

How do you clean a MAF and just what is it?

Why not explain just what numbers the OP should be seeing.

Explain just what fuel trims are and what numbers are good?

 

I wasn’t aware the 5VZ had an EGR. Mine doesn’t anyway.

 

@cr500taco 17 mpg on the highway isn’t too terrible, but I’d expect a bit better with your setup. 9-11 in town is very bad though: you’re in Land Cruiser territory there. Be sure to check for codes. It’s possible your valves might be out of adjustment and/or your fuel system is out of whack, causing it to run rich.

 

Don't drive any other vehicle and why would that matter?
Always do regular fluid maintenance. The trans fluid was replaced 2nd half of last year.
I have a k&N air filter and clean it about once a year. Haven't done the plugs and wires, since the rebuild was put in.

 

The only codes I'm getting are p0171 and p0125. But, both have just started, recently. I have a transmission leak, so I'm sure that's throwing the p0171. Everytime, I top off the trans fluid, it stops throwing the code for awhile. Not sure yet what's throwing the 0125 code. I fixed a coolant leak and changed the coolant this last weekend. But, the code came back this morning. I cleared it after and it didn't come back on yet.

 

The P0171 code is almost certainly the cause of your poor fuel economy. I searched for a thread on here and it ended up being the fuel pump for this person. I’m not saying that’s your issue; it was just the first thread to come up.

https://www.tacomaworld.com/threads/p0171-solved-finally.330233/

 

Some people compare driving a V8 Truck with a 4 cylinder on a unconscious level.

I get that quite often.