I was getting 20-25mpg, all of a sudden I am getting 10-15. It still runs like a top, not skipping, not smoking, lots of power.

I am not getting a check engine light, but tried to jumper the t-e1 and it gave me nothing.

Ideas? Really want to go camping this weekend, but can not afford it getting such poor mpg. I would rather try tests then replacing parts due to money concerns.

 

a restricked air filter or exhaust can hurt the mpg . also a dirty maf sensor .

 

Noted, Will try the air filter, it is cheap. Is there a way to check the exhaust for blockage without tearing it apart?
Thanks for the reply!

 

Jack up a wheel and turn it, hear the brakes dragging on it?

That's what's killing my mileage right now.

 

Check the coolant temp sensor (ECT) to make sure it's telling the computer to go into closed loop. Either by removing and putting in pot of water:
http://personal.utulsa.edu/~nathan-b...40engineco.pdf
Or by checking voltage at the ecu (I find it easier, plus you're verifying the wiring also) Page EG1-124:
http://personal.utulsa.edu/~nathan-b...27troubles.pdf

Run the feedback voltage test on the O2 sensor to make sure it isn't all gummed up. Spec is 6 switches of voltage in 10 seconds but 8 or more is better.

http://personal.utulsa.edu/~nathan-b...42oxygense.pdf

 

the exhaust is hard to check.my converter had burned out to the point, that what was left of the core was blocking the outlet . if you don't have a power lose it is probably not it.

 

Sounds like you need to tear that engine apart!!

 

Thanks everyone for your input. I wound up going camping anyhow. It seems that putting around the woods at 25 or less miles per hour it does not use much fuel at all. When I get on the hwy it sucks it up like I would a beam and coke. Did about 100 miles of woods and some wheeling, used much less then a 1/2 a tank, then used the more then other half to go 45 miles home....Does that give any more indications?

I am doing some of these tests today. The engine only has 80k on it, good compression. So it is something else....

 

What transmission?

Check the cat.

 

5spd trans

how do I check the cat.... I know I can take it off and hammer the hell out of the inside with a screwdriver, and hammer, clean it out, then reinstall...

Hate to do that if it is not the issue though... Know of a quick test?

 

Pulling the cat and shining a light through works well, but it's a pain.

You can pull the O2 sensor and see if all of the exhaust tries to come out the hole - but be careful because the exhaust that far forward is hot enough to burn you.

You can take it to an exhaust shop where they can drill a hole just before and just after the cat and read the pressure difference.

You can hold your hand in front of the end of the exhaust pipe and have someone repeatedly rev the motor - with a clear cat there will be distinct blasts of exhaust, with a clogged cat it will be a more gentle exhaust with less noticeable blasts.

Does the truck roll freely? If you take it out of gear while moving down the road, does it continue cruising along or does it noticeably slow down?

How do the plugs look?

Did you check out the ECT & O2 sensor?

 

umm. try cleaning the upper/lower intake, they tend to get grimy pretty quick, people say they rob power, but mine is loaded up andi can barely tell a difference in power

 

Do a routine maintenance tune up. I.E. plugs, wires, rotor, cap, valve lash, fuel filter, oil change, belts, pvc valve. Basic stuff. If you have yet to do most of this stuff already you most likely are due. Most of it's cheap easy stuff to perform and will give you a starting point. Don't dig into the intake and other stuff until you have properly taken care if your motor. Trust me this can get expensive if you don't start the right way with checking the basics first.

 

Oh yeah and use the toyota oem stuff if you can. these little motors like the oe stuff. Although expensive it will get you results with the confidence it will last like a toyota should.

 

mightymouse has the good advice