EXTREMELY poor MPG

Hey guys, I have a 2000 tacoma 2.7L 4x4 and recently it has had a very sudden decrease in MPGs. I can usually get almost 340 miles/tank combo city/hi way but the last couple of full-ups have yielded less than 150 miles/tank. Please help! I've considered the O2 sensors and spark plugs, but any input would be great as I'm going broke on gas expenses. Thanks!

 

Dirty MAF, throttle body, clogged cat, clogged air filter, list goes on. Use the search function, there was a similar thread on here recently. Might help you out

 

My 03 with the 3.4 gets ~13 MPG, mixed driving

 

Yikes!. Thirsty truck. Have a 90's GM BBC throttle body dually that gets about 3-7 miles depending on the day.

A code scanner in your future and take a whiff of the oil stick,,make sure it's not heavy fuel scented.

Sticking injector maybe?..Never cracked one apart to see the guts or had one go bad.

 

Any other symptoms?

Missing?
Poor performance?
CEL?

Recent work that might have gone wrong?

 

MAF sensor as already mentioned did the trick for me, air up your tires to spec as well, buy a K and N Filter, change your oil and maybe have a tune up. I picked up 4mpg after doing all those things no lie. Same set up as you but mine is a 97

 

No CEL, and my tires are up to spec. I did an oil change 400 miles ago with no recent engine mods. Looks like I'm gonna clean the MAF. How should I do that?

 

Oh, and no lack of power and no misses.

 

Don't put a k and n in it. It does not filter nearly as well as a stock paper filter. Also yields very little in mpg if any.

 

Correctomundo!

 

Normal power and sudden bag mpg and no cel is an odd combo.

The last time I had that issue the neighbors kid was stealing gas. After a few odd trips to the pump, did the math and found I was missing almost exactly 5g worth of miles

 

That sucks! I have an 02 DC 4wd with 200+ on the front and a lift and I get 17mpg

 

Just after shutting it off, do you smell gas when you pop the hood?
Any gas leaks anywhere?

Accidentally left in 4WD ?

 

I haven't tried that.. No it's not in 4wd. I'm not worried about gas thieves because I have a locking gas door with no evidence of tampering.

 

Had another FI rig that had a cracked return line and bad mileage.

 

Update: my truck had a difficult time starting last night, but now it's running fine and fuel mileage seems to be back to normal.

 

True taco fashion...problem fixed itself!


Sounds like you may have had a clog somewhere and it got blown out.

 

You know, that may be it. I forgot a had just recently seafoam-ed it. Maybe something got hung-up or something.

 

That exact scenario happened in my jeep years ago.

 

FTFY