2003 Pontiac bonneville sle 3.8l v6 series II engine

Question

P0300. Need to know exactly what the cause is. Replaced downstream H02S already. And still get also code p0134. For over a month messing with this car I bought used

Answer 1

Hi there,

Unfortunately, I can't give you the exact cause, but I can point you in the right direction to narrowing down the cause or causes.

P0300 indicates misfires on random cylinders. Here is a list of possible causes.

P0300 PONTIAC - Cylinder Misfire Detected Random Cylinders

Read more: https://www.autocodes.com/p0300_pontiac.html

The P0134 indicates an issue with the heated O2 sensor on bank 1. Here is a list of possible causes.

P0134 PONTIAC - HO2S Circuit Insufficient Activity Bank 1 Sensor 1

Read more: https://www.autocodes.com/p0134_pontiac.html