Scratchin my bald-ass head here.

[PetroleumJunkie412]

Right. But the problem arises when that air straight from the enigne bay, passes through the PCV and enters the intake manifold behind the Throttle body. That air straight from the engine bay didn't pass through the MAF. Any air that enters the combustion chamber has to pass through the MAF, or it is what is called unmetered air. The computer knows it's there via the o2 sensors, but doesn't know where it came from. So it is technically a vacuum leak. if it doesn't make it run bad, it'll give you lean codes. The computer has the freedom to richen the mixture a little. Once it does that, if the o2 sensors still detect too much oxygen in the exhaust, you get the CEL.

When is the last time you plugged a scan tool into your truck?

 

[cbxer55]

Last weekend. I posted earlier that I have as shit-ton of codes. O2 sensors, O2 heaters, EGR deleted, EVAP deleted, bank 1 and 2 lean codes. Monitors are a mess. Even though the MAF apparently is not working, I don't have a code for that. Yet, it runs freakin awesome. I don't know how. but it sure does. Checked gas mileage Tuesday, 261 miles, 12.7 gallons. 20.55 mpg. For a 3.0 that is outstanding. And I am not driving it like a grandpa. I thrash it like a rented mule.

Guess I'm at the "If it ain't broke, don't fix it stage".

 

[Curious Hound]

Guess I'm at the "If it ain't broke, don't fix it stage".

I Think you're acting more like this.

 

[PetroleumJunkie412]

Last weekend. I posted earlier that I have as shit-ton of codes. O2 sensors, O2 heaters, EGR deleted, EVAP deleted, bank 1 and 2 lean codes. Monitors are a mess. Even though the MAF apparently is not working, I don't have a code for that. Yet, it runs freakin awesome. I don't know how. but it sure does. Checked gas mileage Tuesday, 261 miles, 12.7 gallons. 20.55 mpg. For a 3.0 that is outstanding. And I am not driving it like a grandpa. I thrash it like a rented mule.

Guess I'm at the "If it ain't broke, don't fix it stage".

If you're getting codes, they are not deleted. You just removed parts.

Deleting is done at a pcm level.

Without removal of a PCM's ability to detect a fault, it will set a trouble code and enable open loop fuel and spark tables.

In your year truck, open loop is limp mode, and is severely de-tuned from normal running condition. Your fuel economy has been "good" likely because the truck is programmed to "run well enough to get it to a garage." So, while you are enjoying satisfactory fuel economy, it is important to remember, it absolutely is not running right.

It's why your MAF is not operating, or is only being used as a reference. Your truck (depending on year) is likely running on an alpha-n or speed density fueling strategy. Both are inferior to MAF with the ability to set trims.