2002 Tacoma 4x4 Awful Gas Mileage

My 96 4X4 will only get 15mpg in town driving and thats if I drove gently. 31 10.50 15's, automatic, 175k miles, Flatland bumper and winch (heavy, heavy).

 

change your spark plugs, clean your MAF sensor, clean the throttle body, change your air filter, replace your PCV valve, use a couple doses of B12 chemtool (make it strong, like only fill up 1/2 tank at most), then a dose of Techron concentrate.

Your MPGs shouldn't be that bad. I'm getting like 18 MPG on the highway and my truck is heavy.

 

I remember when I first got my truck, from filling up at the gas station to where the needle would finally start to go down, would take about 70 miles.

Now, the needle starts going down after fill up once I hit about 25 miles lol

 

Yea I know the feeling. Good thing it’s not my daily. With my beater I get around 380 miles before I have to fill up (11-12 gallons) compare to 200 miles (15 gallons) on my Tacoma. My Softopper also creates drag and decrease 1-2mpg so I try to have it down when I don’t need it.

 

My 1999 2.7L 4x4 was doing bad on MPG until I had the Catalytic converter replaced with a Magnaflow universal cat and replaced the fuel filter. Gets much better now.

 

OP,
What motor and trans do you have?
The Magnaflow catalytic converter is awesome. It improved the low end on my 2.7 (3RZ) motor. I have an auto trans and my truck weighs in just under 4,300 pounds and I’m getting 15-17 mpg’s.

 

Magnaflow is the only good aftermarket option for catalytic converters, particularly if you need them to meet CA smog specs. I had to replace mine a few years ago and got the CARB certified Magnaflows and they've held up great so far. Far, far cheaper than OEM cats. Although OEM cats are the best quality ones you can get hands down.

 

Don't go replacing your cats though unless you need to...usually you'll know by the dreaded P0420 code, or when your truck's performance tanks due to one or both getting plugged up

 

Like others have said...start simple. I would start with spark plugs and PCV valve...shouldn't cost more than $20-25 for it all unless you don't have the tools. But you should get the tools if you don't already have them.

 

Oh P0420, I know thee well.

 

Shhh...say it too many times and it will come back to haunt us


Fortunately I just passed my biennial smog test last Saturday so either way I'm good for another 2 years lol

 

The CEL isnt on, and I went and got the ecu flashed. No codes. Im going to replace the O2 sensor tomorrow to see if it fixes anything.

 

I actually just checked how far it is to work. Its 19 miles one way. 38 miles and a quarter tank of fuel isnt great. Guess i thought the drive was longer, turns out my gas mileage is even worse

 

Its the 3.4L V6 with a 5 speed. The 4x4 taco gearboxes are awful. At cruising speed on the highway im sitting at 3000 rpm, but even driving slowly im not doing much better gas wise. Im hoping to get a new exhaust soon, hopefully it fixes some things.

 

The one which will impact MPG is your AFR (Air Fuel Ratio Sensor), not the o2 sensor. The AFR is upstream and expensive. When replacing AFR or o2, stick with Denso. None of those cheap aftermarket sensors.

Like most mentioned, start simple. Give it a good tune-up and see where you are. I wouldn't replace the sensors unless you are throwing codes. Save the AFR for later.

As for what you can expect, realistically - I'd be content with 14-16 MPG. Our trucks (especially 3.4 DC) are not known for fuel efficiency.