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2003 Deville base
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43 Posts
Discussion Starter #1
code reader say's STFT B-1 S-2 is 99.2% what should i do to correct? all others are good. this is an 03 deville base.
 

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2000 Deville base 2019 Corvette Gran Sport
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971 Posts
Obviously your car has a extremely LEAN condition hence why your car computer is adding fuel. These are the conditions why your car can run lean:

Air or vacuum leaks in the intake manifold, near the throttle body or at vacuum hose connections.

Weak fuel pump that is not generating enough pressure or volume

Fuel line restrictions (like a pinches hose or plugged filter)

A weak fuel pressure regulator that is not maintaining adequate fuel pressure

Air leaks in the PCV plumbing

Dirty MAF (Mass Airflow) sensor that is under reading airflow into the engine

Dirty or dead fuel injectors

Ignition misfire (a fouled spark plug, weak ignition coil or bad plug wire that causes a misfire allows unburned oxygen to pass into the exhaust and fool the O2 sensors)

Compression leaks (bad exhaust valve that allows unburned oxygen into exhaust and fools O2 sensors)

Exhaust manifold crack or gasket leak (allows unburned air into exhaust and fools O2 sensors)

Bad O2 sensor (signal shorted to ground so the sensor reads lean all the time)
 

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-Administrator- 2002.5 F55 STS 2014 FWD Explorer
Joined
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66,595 Posts
B1S2 is the after-cat O2 sensor. What DTCs are showing in the car's built-in code scanner/memory system ?
 

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2003 Deville base
Joined
·
43 Posts
Discussion Starter #4
Obviously your car has a extremely LEAN condition hence why your car computer is adding fuel. These are the conditions why your car can run lean:

Air or vacuum leaks in the intake manifold, near the throttle body or at vacuum hose connections.

Weak fuel pump that is not generating enough pressure or volume

Fuel line restrictions (like a pinches hose or plugged filter)

A weak fuel pressure regulator that is not maintaining adequate fuel pressure

Air leaks in the PCV plumbing

Dirty MAF (Mass Airflow) sensor that is under reading airflow into the engine

Dirty or dead fuel injectors

Ignition misfire (a fouled spark plug, weak ignition coil or bad plug wire that causes a misfire allows unburned oxygen to pass into the exhaust and fool the O2 sensors)

Compression leaks (bad exhaust valve that allows unburned oxygen into exhaust and fools O2 sensors)

Exhaust manifold crack or gasket leak (allows unburned air into exhaust and fools O2 sensors)

Bad O2 sensor (signal shorted to ground so the sensor reads lean all the time)
Wow thats a lot of stuff... thanks for replying.
B1S2 is the after-cat O2 sensor. What DTCs are showing in the car's built-in code scanner/memory system ?
P0410 was showing but stopped when i checked to make sure the secondary air pump was working correctly and i found a vacuum hose that i forget to reconnect. gonna drive around to see if this code comes back. Thanks for the reply.
 
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