2003 taco went 17mpg to 9 mpg

Hello everyone!

I’ve not changed anything, and I’m losing 9 mpg in fuel. I’m ve double checked the numbers 7 full tanks now. I feel it’s slowly getting worse. A couple months ago I was getting 12. No check engine lights, I’ve replaced the fuel filter. This truck has it out for me ha ha. Two mechanics I’ve asked had not one idea. Toyota charges $175 to to find a problem. I’m a woman who lives in California and mechanics love to try to play me. She has probably 250k (the miles were rolled back before I stupidly bought it based on a fake vin). Ideas would be appreciated.

 

Give us some info on the truck type, engine, tires, lift auto, any engine maintenance?
Can be a lot of things or combination of things.
Air filter, injectors, plugs,MAF , bad cat,etc

 

I'd check for a fuel LEAK first. Then see if the exhaust is rich. Find somebody with a OBD][ reader and see if you can gather any additional data. Just a place to start looking.

 

No leaks that I can tell. I will look for that OBD reader. Thank you!

 

Have you noticed a loss in power as well?

 

Start with new spark plugs

 

No loss in power

 

Kalifornia? E-85? Try mid grade gas.

 

That will cost a small fortune in itself ha ha!

 

Where do you live? When was your last service?

 

Double check your fuel tank for a plug. Gas thieves have taken to drilling holes in tanks, and the ones with more than one brain cell plug the hole so they can keep coming back to fill their cans.

 

My last time up was a couple of years ago in lovely San Diego. I’m going to go get the spark plugs replaced tomorrow.

 

Do air filter too