Question

2001 Buick Regal, engine drops in & out constantly when acc. pedal is released. I have the engine codes p0171, p0404, p0405, p0420, and p0716

Answer 1

P0171 BUICK - Fuel Trim System Lean Bank 1
Read more: https://www.autocodes.com/p0171_buick.html

P0404 BUICK - Exhaust Gas Recirculation Open Position Performance
Read more: https://www.autocodes.com/p0404_buick.html

P0405 BUICK - Exhaust Gas Recirculation Position Sensor Circuit Low Voltage
Read more: https://www.autocodes.com/p0405_buick.html

P0420 BUICK - Catalyst System Low Efficiency Bank 1
Read more: https://www.autocodes.com/p0420_buick.html

P0716 BUICK - Transmission Input/Turbine Speed Sensor Range/Performance
Read more: https://www.autocodes.com/p0716_buick.html