2.7 is getting 12 mpg Please help

I have had my Tacomaabout 2 years now and have noticed that it gets terrible gas mileage for a 2.75 speed 4wd. I have tried just about all I can I just can’t figure this out Iam getting around 12 to 13 mpg and have had new coils and wires also did a fuelfilter with a fuel injection cleaning. Also put a new mass air flow sensor on.Now here might be my issue I want to get feed back from you guys I replacedboth 02 sensors with the wrong sensors the front sensor fits a non calif esv4wd and the rear sensor is calif esv 2wd the truck was made in calif with califesv. Also one last bit of info when the rpm get up to 3 grand the truck smokesblack smoke like a diesel. My question is if I get the correct sensors willthat solve my problem or do you guys think it is something else.



Thanks in advance with any information.

Jon

 

Due to the fact that the A/F mixture is adjusted by what voltage the ECU sees from the O2 sensor, I think that it would be a perfectly reasonable explanation for the problems you're having. Sounds like your truck is running very rich, which can damage the catalytic converters. This is something I would want to fix right away and not continue to drive on.

 

X2

 

check your engine temp sensor too. If it is gone it might be running rich like a cold start condition.

 

Thanks for the input guys I took it to my buds and we put it on a computer to see what the volts the o2 sensor was getting. The front never got over .90 and the rear never got over 1.1 I will replace the sensors ASAP hopefully that's the problem.

 

Did replacing the O2 sensors fix your mileage problem? I am considering replacing mine and want to know if it worked...
Thanks