Swapping Intake gaskets for a P0171 & P0174

[Keiterburb]

So I went on the road to travel for work last week and as soon as I left my wife said we have an engine light on. I had her run codes and found a P0171 and P0174. The temps had dropped into the teens for the first time this year. After some research it sounds like intake gaskets leaking. I did't do any real diagnostics as the engine was running fine when I returned and temps were back in the 50-60s. I needed to change the oil pressure sensor as well so at least this was a good opportunity to replace it. Also doing the knock sensors today before putting it back together. The previous owner had wired a knock sensor into the front of the passenger cylinder head!

 

[PNWYukon]

• DTC P0171 Fuel Trim System Lean Bank 1
• DTC P0174 Fuel Trim System Lean Bank 2

CONDITIONS FOR SETTING THE DTC
The long term fuel trim weighted average value is more than a calibrated value for 2 seconds.


Excessive resistance in the fuel injector control and/or the ignition 1 voltage circuits may cause the following symptoms:

• A lean condition
• MisfireThe system may become lean if an injector is not suppling enough fuel.
• A lean condition could be present during high fuel demand.
• Review the Failure Records with a scan tool. If an intermittent condition is suspected, refer to Intermittent Conditions.

 

[Keiterburb]

Been running great since replacing the gaskets. Fixed the oil sensor and knock sensors with harness while I was in there. Does anyone else hate the fuel injector plugs?

 

[swathdiver]

The previous owner had wired a knock sensor into the front of the passenger cylinder head!

That's where they put them on the Gen IVs. Nice work btw!

 

[Ilikemtb999]

Just did mine a few weeks ago on my newly acquired Yukon. Was running decent then we got a cold cold morning and could barely keep it idling till it warmed up. Went to the auto parts store, got a set of gaskets and came home and did them. All is well.