P1174 2008 Yukon Denali

[02Lightning]

Where do I start? I put NTK front o2 sensors in about a month ago. No problems with the old, just maintenance.

 

[kbuskill]

Where do I start? I put NTK front o2 sensors in about a month ago. No problems with the old, just maintenance.

Check your ethanol percentage with a Tech 2 or an OBD2 adapter and Torque Pro app.

 

[wsteele]

Does the engine idle rough or have any other symptoms (like hard starting) or just the code?

 

[Fless]

And what do your long term and short term fuel trims look like, at idle and at 2000 rpm? Both banks...

 

[91RS]

Replace the oxygen sensors with OEM ones only. Make sure the air filter is good quality (OEM also recommended) or if it is a K&N or similar with oil make sure the oil hasn't coated the MAF. Make sure all the intake duct clamps are tight and the duct isn't rolled. Make sure all the PCV tubes are connected and not broken. Make sure the oil cap and dipstick seals are good. No exhaust leaks. If none of those issues are present and the code still returns with the OEM oxygen sensors (pre cat) then you will likely need injectors (and do NOT buy the cheapo knockoffs on eBay and Rock Auto).

 

[02Lightning]

Check your ethanol percentage with a Tech 2 or an OBD2 adapter and Torque Pro app.

I have the Torque Pro app, I didn't think think vehicle had a flex fuel sensor?

 

[02Lightning]

Does the engine idle rough or have any other symptoms (like hard starting) or just the code?

No other symptoms.

 

[02Lightning]

And what do your long term and short term fuel trims look like, at idle and at 2000 rpm? Both banks...

Not sure of that, I'll have to look and see how to do that on Torque Pro if I even can.

 

[02Lightning]

Replace the oxygen sensors with OEM ones only. Make sure the air filter is good quality (OEM also recommended) or if it is a K&N or similar with oil make sure the oil hasn't coated the MAF. Make sure all the intake duct clamps are tight and the duct isn't rolled. Make sure all the PCV tubes are connected and not broken. Make sure the oil cap and dipstick seals are good. No exhaust leaks. If none of those issues are present and the code still returns with the OEM oxygen sensors (pre cat) then you will likely need injectors (and do NOT buy the cheapo knockoffs on eBay and Rock Auto).

I thought NTK made the sensors for GM? I did valve cover gaskets about a month ago, along with cleaning the MAF, throttle body and replacing the front 02 sensors, I will go thru and recheck my work. I did just find out I have an oil leak, from intake valley tray, so I'm hoping maybe it's caused a vacuum leak? I have parts ordered and on the way for this. I would have thought an engine light would have showed up after a month with new O2 sensors.

 

[02Lightning]

Another thought here, I'm getting ready to pull the intake to change the valley tray gasket because of an oil leak. If I pull all the injectors and swap sides the codes should follow right? If the code stays the same I can eliminate the injectors right?