I have a grand prix gt 2006 with 125k miles. I replaced spark plugs and wires, ran some techron through motor, and cleaned the throttle body. Within about a week of this a check engine light came on, code p0053 and p0128. p0053 is the o2 sensor and p0128 is a coolant issue. I started small and replaced o2 sensor and filled and purged any air in the coolant system. I rest the light and it is back with the same codes plus one more... p0030 which is part of the o2 system again. I am going to replace the thermostat this weekend but I don't know where to start on the o2 issue. Any thoughts on where to look for the gremlin?
Originally Posted by Fivefingerdeathpunch
