Running too lean?

[gfunkfb09]

My check engine light came on and I had Advanced Auto Parts scan for the code.

It came back as my yukon running too lean, and it was giving an error on the 2nd knock sensor.

Has anyone else run into this problem?

They told me it could be a bad knock sensor, bad MAF or a clogged fuel filter.
What do ya'll think?

I cleaned the MAF today and that didn't solve the problem, I got the same error last week and when I put more gas in the check engine light went off and today it came back on. And around Thanksgiving my fuel pump went out and I got a new one of those.

Thanks guys!

 

[blueflamed03]

Is yours FlexFuel? Or regular? If so, changing fuel filter is easy....and may be a good change anyway.

 

[gfunkfb09]

Its FLEX

 

[blueflamed03]

a little more in detail, search Youtube, but i'd get it changed.

 

[gfunkfb09]

I will try that first then since its the cheapest.

 

[gfunkfb09]

I bought a new filter today and am going to tackle the task of changing it later. Are there any tips and tricks to getting it changed? I haven't been able to find much about it else where.

 

[07Burb]

I know the one's for regular fuel are really easy and are inline right along the driver's side frame rail but I'm not sure how the Flex Fuel filters may be set up differently. Do you have an idea of where your fuel filter is located and a pic of what it looks like?

 

[gfunkfb09]

I haven't looked yet, im assuming thats where it is though.

What tools do I need?

Do I need to depressurize the fuel system? if I do, how?

 

[gfunkfb09]

I'm having the hardest time getting that filter off! How do you get the clamp end off?

 

[Mr.Martin]

Flex fuel has a plastic clip thing on one end. There is a little tool made to remove it but I just used a flat head screw driver and patience.

This is what the right tool looks like

http://www.sjdiscounttools.com/ast8022.html

 

[killer20072001]

I had a running lean code also. I did some donuts and it went away!!! No joke. Its been gone for a few weeks now but I wont be surprised if it comes back.

 

[gfunkfb09]

Nice killer! What size flat head did you use and how did you get it under the clamp?

 

[07Burb]

Is that what a mechanic does to fix it too? Go do donuts in the parking lot to make the code go away

 

[killer20072001]

Apparently thats the secret they are not telling us. They just make you buy a bunch of parts pay for labor and then go bust some sweet donuts to fix the problem. Basterds!

 

[gfunkfb09]

Where can I buy this special tool in a store?

 

[killer20072001]

Just go to O'reillys or an Autozone and tell them you need a fuel filter remover tool. They will know what you are talking about.

 

[gfunkfb09]

Finally got it off today and changed out. I had to buy the Lisle 35000 GM Flex Fuel Filter removal tool. I found it at O'reillys, Autozone had no clue what it was. It is the only tool I could get to fit and its made for it lol. I got it off in about two seconds with it. I swapped the filters and my check engine has gone off, so I'm guessing I found the culprit and fixed the problem.