[RJC]

110k miles. Brake booster failed, replaced. Around that time noticed I started plowing through gas. Cleaned k&n and recharged. Changed plugs, carbon build up on plugs and exhaust. Boost is slow/sluggish. Added some chevron techron. MPG is still crap... used to live at around 17-18 around town. I'm driving between 6 to 7k ft above sea level. - Ideas or toughts?...

 

[Justinjs]

110k miles. Brake booster failed, replaced. Around that time noticed I started plowing through gas. Cleaned k&n and recharged. Changed plugs, carbon build up on plugs and exhaust. Boost is slow/sluggish. Added some chevron techron. MPG is still crap... used to live at around 17-18 around town. I'm driving between 6 to 7k ft above sea level. - Ideas or toughts?...

What's the MPG now?

 

[RJC]

What's the MPG now?

16.2 an avg of highway and city

 

[DNA Dan]

Tires? Racks? Topper?

What do LTFTs look like? It can tell you if the truck is running rich.

 

[RJC]

What are LTFT?

 

[DNA Dan]

Long Term Fuel Trim.

Basically the Short Term Fuel Trim (STFT) tracks almost instantly with changes in air volume. If it consistently sits high or low relative to zero, it adjusts the LTFT to compensate for the new baseline. This way STFT can remain close to zero. So basically the STFT is what the truck is currently seeing, the LTFT is what the truck is seeing over a longer period of time. If it's excessively negative, that means you're running rich and the PCM is calling for less fuel (shorter injector pulse). If they are positive, that means you're lean, because the PCM is calling for more fuel (longer injector pulse). You won't trigger a code until LTFT exceeds +/- 20.

 

[RJC]

How can I look into this?

 

[Justinjs]

Long Term Fuel Trim.

Basically the Short Term Fuel Trim (STFT) tracks almost instantly with changes in air volume. If it consistently sits high or low relative to zero, it adjusts the LTFT to compensate for the new baseline. This way STFT can remain close to zero. So basically the STFT is what the truck is currently seeing, the LTFT is what the truck is seeing over a longer period of time. If it's excessively negative, that means you're running rich and the PCM is calling for less fuel (shorter injector pulse). If they are positive, that means you're lean, because the PCM is calling for more fuel (longer injector pulse). You won't trigger a code until LTFT exceeds +/- 20.

Could you use Forscan to check this??

 

[DNA Dan]

Not sure. Any regular scanner should be able to read that PID.