Codes P0171 and P0174

[00LS12LS6Z28]

I have these codes which mean I am running lean on bank 1 and bank 2. I was told that the MAF needs to be cleaned or it could be a O2 sensor. Anyone experience this? The only thread we have on this was also involving a cam issue. A tune was done to solve the issue. Let me know your thoughts. Thanks

[35th-ANV-SS]

Running lean on both banks almost always says vacuum leak.

[importhater81]

I have these codes which mean I am running lean on bank 1 and bank 2. I was told that the MAF needs to be cleaned or it could be a O2 sensor. Anyone experience this? The only thread we have on this was also involving a cam issue. A tune was done to solve the issue. Let me know your thoughts. Thanks

Does your car have any modifications?

[SMWS6TA]

Check your pcv hosing at the pcv itself and at the back of the intake where the hose splits. These are the two most common areas that cause a vacuum leaks. If you hose is cracked, torn or like in my case fell apart in my hands there are a couple of fixes in the tech stickies.

[00LS12LS6Z28]

Does your car have any modifications?

Yes, LS6 intake and I have the Granatelli MAF. I am thinking of putting the stock one back on. I also have the K&N FIPK, which is the air filter with the air box removed. Those would be the only mods that I can think of affecting it. I have an exhaust and headers put on back in 04, but they never threw a code. Once I put the LS6 intake and LS6 cam in, the light has been on.

[00LS12LS6Z28]

Check your pcv hosing at the pcv itself and at the back of the intake where the hose splits. These are the two most common areas that cause a vacuum leaks. If you hose is cracked, torn or like in my case fell apart in my hands there are a couple of fixes in the tech stickies.

Thanks, I will have to take a look.

[00LS12LS6Z28]

Running lean on both banks almost always says vacuum leak.

Besides the pcv hosing and the pcv itself, what could be other places to check?

[importhater81]

Yes, LS6 intake and I have the Granatelli MAF. I am thinking of putting the stock one back on. I also have the K&N FIPK, which is the air filter with the air box removed. Those would be the only mods that I can think of affecting it. I have an exhaust and headers put on back in 04, but they never threw a code. Once I put the LS6 intake and LS6 cam in, the light has been on.

Headers in 04? and a Ls6 intake recently? What did you use to plug the egr passage off the headers? I'm assuming the headers you are running has an egr pipe if you were running a Ls1 intake before the Ls6.

Aftermarket MAF's are junk,Id' put the stock one back on and see what happens.

[35th-ANV-SS]

Besides the pcv hosing and the pcv itself, what could be other places to check?

My guess is that your intake is leaking since you just changed it and you've had codes ever since.

[bad4ss]

I popped the screen those codes came up so I changed the maf and it was good. It might be the maf

[SMWS6TA]

if your leaking vacuum from the intake you can take some carb cleaner around the intake a little at a time and listen for a surge. If it surges that is where your vacuum leak is.

[35th-ANV-SS]

if your leaking vacuum from the intake you can take some carb cleaner around the intake a little at a time and listen for a surge. If it surges that is where your vacuum leak is.

This is how I found my leak on my V6. I've heard though that carb cleaner on a plastic intake will cause it to leave residue on the intake. So if you do this, be sure to wipe it down right away.

Another way is to smoke test it. That will tell you exactly where the leak is in the system.

[00LS12LS6Z28]

Thanks for all the input. My friend states it is an exhaust leak. Maybe headers or intake.....

[lingenfelter69]

On my 03 Z06, I had the same codes. I put in super premium, and tightened my cold air intake connections and the light is off now.