Hi,
I'm having an issue with my:
2016 Chevy Silverado 5.3L V8, 76.5k miles
P0171
Symptoms: Truck runs fine mostly but has about a 10% reduction in fuel economy. After running for a while and idling, randomly, the truck will experience a rough idle during which short term fuel trims will spike. The truck starts fine and from what I can tell, has no loss of power while running. Given that rough idle/code takes some time to occur and can often be "reset" by clearing codes, it makes me believe I have a valve or something mechanical that is malfunctioning to create a lean condition.
In the last 2k miles, I have replaced:
Spark plugs and coil packs
Oil and filter change
Air filter check (clean)
Mass airflow sensor
Mass Air Pressure sensor
Ambient air temp sensor
EVAP purge solenoid
PCV Valve
Transmission replaced (stock failed)
At this time, I also had rear diff and transfer case fluid changed
I have smoke tested my air intake and don't see any leaks. I also smoke tested the exhaust system (above) with nothing noticeable. Attaching freeze frame and data log.
Any ideas? Thank you.
1GCVKREC9GZ198543-RepairReport-2023-07-30-04-01-24.pdf
Data log.pdf
1GCVKREC9GZ198543-freezeframe-2023-07-30-03-59-6.pdf
Hi, I'm having an issue with my: 2016 Chevy Silverado 5.3L V8, 76.5k miles P0171 Symptoms: Truck runs fine mostly but has about a 10% reduction in fuel economy. After running for a while and idling, randomly, the truck will experience a rough idle during which short term fuel trims will spike. The truck starts fine and from what I can tell, has no loss of power while running. Given that rough idle/code takes some time to occur and can often be "reset" by clearing codes, it makes me believe I have a valve or something mechanical that is malfunctioning to create a lean condition. In the last 2k miles, I have replaced: Spark plugs and coil packs Oil and filter change Air filter check (clean) Mass airflow sensor Mass Air Pressure sensor Ambient air temp sensor EVAP purge solenoid PCV Valve Transmission replaced (stock failed) At this time, I also had rear diff and transfer case fluid changed I have smoke tested my air intake and don't see any leaks. I also smoke tested the exhaust system (above) with nothing noticeable. Attaching freeze frame and data log. Any ideas? Thank you. 1GCVKREC9GZ198543-RepairReport-2023-07-30-04-01-24.pdf Data log.pdf 1GCVKREC9GZ198543-freezeframe-2023-07-30-03-59-6.pdf