About twenty thousand miles between tune and issues beginning. I should also mention that it was a tune by a really reputable shop called BlackBear. Before and since the tune I have only heard good things about them.

 

Hey Rick thanks. I actually don’t have an aftermarket intake and have searched all over the stock one, but have found no leaks.

 

Just a good scanner, so just about any reputable mechanic shop. I use a Snap on Solus Ultra, and it has the capability to do it.

 

If I get a gm vehicle in here soon that uses inferred alcohol percentage instead of a physical fuel composition sensor I'll make a video on the process of resetting it so you guys can visualize what we are talking about.

 

Here's a south main video on the subject. With lots of helpful info in the video description

 

However, I will say it usually does not cause lean codes like you are getting. But resetting the value is a good idea when chasing fueling issues.





Hey Ross, how do you have your PCV system ran? You don't have an open filter on the valve cover do you? In other words is the PCV system and hoses all stock or did you put any vent filters on the oil cap or valve covers? If so that's your problem.

 

No it’s stock and I replaced the hose for fear of pin holes under the insulation.

 

With it ideling check for exhaust leaks at the header flange with the back of your hand

 

Easier exhaust leak check, use a piece of rubber hose a few feet long, stick one end to your ear and run the other end around the exh flanges. You'll find the leak when you hear a poof of air in your ear. And it allows you to accurately pin point the exact location of the leak.

I actually use a stethoscope with a piece of rubber hose attached to it and a piece of metal brake line stuck in the hose with a 60 or so degree bend in the metal brake line to allow me to get in and under the flanges at the head. Works great for finding vacuum leaks too, you'll hear the air and be able to locate the leak down to an exact area.

Use this method around intake gaskets and injector o rings. Hoses. Hose connections. Brake booster...

Also, do you happen to hear an air sucking sound when you push the brake pedal? Hear it inside the truck? If so the booster is leaking on the inside portion of the truck.

Another thing you can do is watch fuel trims on a scanner while pinching off rubber hoses. If you pinch one and the ft gets better whatever the hose attaches to is leaking. Can't really do that on PCV systems because that can cause a false positive since PCV flow is monitored by the MAF.

Which brings me to another point, pcv valves can cause a bit of an issue too if they flow too much or not enough. So far I've only seen this on Fords though.

 

Fuel composition reset