strange delima

[Rc4r]

My average Mpg is 14, my check engine light came on and now I'm getting 21mpg city? Lol wtf?

 

[4-Ripcord]

That is awesome. whats the code?

 

[Baja Runner]

Maybe a sensor freaking out thinking its running too rich so its leaning out the mixture a bit? Weird.... !!

 

[Rc4r]

That is awesome. whats the code?

I'm a Noob. How do you get the code.

 

[Tucson4runner]

I'm guessing you don't have a scanner so what I do is go to autozone. They will read it for you for free and they can tell you what the code means.

 

[Baja Runner]

You can also buy the OBDII scanners. There are some cheap ones that do the job... Give you the code! Then you just take the code and google it, and find out whats wrong. Simple.

 

[TheDurk]

I'm guessing you get a front O2 code of some kind (P0125, P0130, P0135,P1130,P1135, P1133,etc). What may be happening is the code is locking the ECU into open-loop (start-up) mode where the ECU does not use the O2 sensor to set trim and timing. It does this when it doesn't trust the readings it is seeing from the o2. If it is, change the front o2 and you will clear the code AND improve MPG.