P0131 Cadillac - 98 cadillac deville 4.6 v8

Question

Sets SES light when engine reachs 196 deg no matter what the rpm ,speed or what ever Its allways on Bank1 sensor 1 have changed it a time or two all ready

Answer 1

I would check for intake leaks, fuel pressure (48 -55 psi) and exhaust leaks first. 

and maybe replace the fuel filter and use a good fuel system cleaner like BG 44k or 3M 

you can go through diagnostic procedures below 

Possible causes

- Faulty Front Heated Oxygen Sensor (HO2S) Bank 1

- Front Heated Oxygen Sensor (HO2S) Bank 1 harness is open or shorted

- Front Heated Oxygen Sensor (HO2S) Bank 1 circuit poor electrical connection

- Inappropriate fuel pressure

- Faulty fuel injectors

- Intake air leaks may be faulty

- Exhaust gas leaks