Fresh meat

[OIFYukon08]

Just bought a new to me 08 Yukon XL SLT 5.3 flex with some issues. Assumed it was typical AFM issues (did have a stuck #6 valve) but of course there's more. Runs rough keeps going into open loop and gas tank will read empty runs rough regardless. Waiting on a better scan tool I just ordered after reading a few posts and already have alldata for it but I'm sure ill need some help from those who have delt with these more on this one from what im seeing so far and hopfully can help some as well with 20ish yeats in the automotive field

 

[Miami-Dade]

Welcome from Miami!

Moved you here for your issues.

Just bought a new to me 08 Yukon XL SLT 5.3 flex with some issues. Assumed it was typical AFM issues (did have a stuck #6 valve) but of course there's more. Runs rough keeps going into open loop and gas tank will read empty runs rough regardless. Waiting on a better scan tool I just ordered after reading a few posts and already have alldata for it but I'm sure ill need some help from those who have delt with these more on this one from what im seeing so far and hopfully can help some as well with 20ish yeats in the automotive field

 

[Geotrash]

Just bought a new to me 08 Yukon XL SLT 5.3 flex with some issues. Assumed it was typical AFM issues (did have a stuck #6 valve) but of course there's more. Runs rough keeps going into open loop and gas tank will read empty runs rough regardless. Waiting on a better scan tool I just ordered after reading a few posts and already have alldata for it but I'm sure ill need some help from those who have delt with these more on this one from what im seeing so far and hopfully can help some as well with 20ish yeats in the automotive field

The scan tool should reveal all. Without it, we're all guessing. But once you have the codes, we likely know 99% of the root causes and can help guide you.

My gut says it's the fuel pump and possibly a bad ground. These things go all wonky when there's a weak ground. Search for "Big 3 upgrade" in here. The battery and ground cables slowly corrode from the inside out. They look fine but can't carry the current. And there are several ground points in the genie compartment that should be removed and cleaned as part of any troubleshooting process like this.

 

[OR VietVet]

Welcome to the forum from Oregon.

 

[Joseph Garcia]

Welcome to the Forum from NH.

Lots of knowledgeable folks here who freely share their knowledge, experiences, and perspectives. Knowledge is power.

I hope that you will become a participating member in the Forum's discussions.

Pics of the truck, please.

 

[BlackBearPerf]

Welcome to the forum from Northern Idaho!

 

[Hoesgottaeat2]

Welcome from NY!