P2099 and p2097 together

[Rogerp]

Just got these codes. What should I look for first? 2014 Silverado 185k seems to be ri Ning fine. Thanks!

[rav3]

This is from Google search.

 

 

GM codes P2097 (Bank 1) and P2099 (Bank 2) both signal a Post Catalyst Fuel Trim System Too Rich, meaning your engine's computer detects excess fuel after the catalytic converter, often pointing to issues like exhaust leaks, faulty downstream O2 sensors, bad fuel injectors, or sometimes even a restricted air filter or bad fuel pressure regulator, requiring checks for vacuum leaks and proper sensor/exhaust function on both sides. 

[newdude]

Assuming you have no intake or exhaust leaks or vacuum leaks, fuel injectors are a likely culprit on these direct injected V8s.  

 

Another thing to consider is oxygen sensors, especially if you've had them replaced recently with non OEM ones.   

 

P2097/P2099 diag tips:

 

• The post catalyst fuel trim diagnostic is very sensitive to heated oxygen sensor (HO2S) design. A non-OE sensor or an incorrect part number may cause a DTC to set.
• Certain aftermarket air filters may cause a DTC to set.
• Certain aftermarket air induction systems or modifications to the air induction system may cause a DTC to set.
• Certain aftermarket exhaust system components may cause a DTC to set.

Edited December 29, 2025 by newdude

[Rogerp]

Thanks will check out your recommendations  much appreciated!

 

One more thing. My engine area has a noise after shutting off engine that is new and sounds like a cooling off click once then a few seconds later again maybe does it three times. Could that be a loose bolt on exhaust manifold?

Edited December 30, 2025 by Rogerp