Hullo all. I have a 06 Mazda3s with the 2.3l and 142k miles. The problems started with a rough idle so I cleaned the TB which didn't seem to help. Still feels rough, and the acceleration feels off. Takes a second or two for it to really kick in, and after I left off, it takes another second or two for it to feel like it stops. Kind of a soft jerk sort of. Anyway, I'm getting codes p0131 and p2251 which I know means I need to replace my upstream 02 sensor, so I'm already working on doing that. I'm also getting p0661 which I know is a solenoid from what I've researched. Question is, does any know where I can possibly find this anywhere at all? Looking online has been no help at all. Could all of this be part of the idle and acceleration problems? Or could it all be something much simpler like unmetered air causing all the problems since it's all intake related? Thanks in advance for the help.

 

A code P0131 may mean that one or more of the following has happened:

• Faulty o2 oxygen sensor
• Short to voltage on O2 signal circuit
• High resistance or open on O2 signal circuit

Possible Solutions

• Replace faulty sensor
• Repair short, open, or high resistance on o2 signal circuit

And this here refers to a Hyundai, so some values may not be exactly applicable:

According to the factory manual:

P2251 - Linear O2 sensor reference ground circuit/open (bank1, sensor 1)
(this is the front sensor)

Disconnect ECM plug and front O2 sensor plug.
Measure resistance:
1 - O2 term 1 and ECM term. 41.
2 - O2 term. 2 and ECM term. 53.
3 - O2 term. 3 and ECM term. 40.
4 - O2 term. 4 and ECM term. 19.

Resistance should be below 1 ohm. If not, you have a short in the harness. If it all checks out, remove front O2 sensor and check to see if it is contaminated, deteriorated, of damaged. This is out of the factory book. It is recommended that the O2 sensor be changed after 80 - 90,000 miles.



In short: the sensors may be bad or the wiring to the sensors may have a short.