Lean Condition, code 172

[SolidState]

Hey guys,

I am a little puzzled at this time.

I recently installed a new 73mm MAF with a custom enlarged sample tube.

Last night after a WOT stint, the car threw a 172 code, suggesting a bad o2 sensor.

Now, the car has sat a while...just over one year to be exact. It has new intake gaskets and the o2s have about 30k on them.

Any thoughts?

Cheers

 

[jbeano]

After I changed my MAF same thing happened. Put the old one back problem gone.

 

[SolidState]

I should also mention that I can hear a whistle in the intake around or near the EGR valve. I haven't been able to pin point it.

The thing that gets me is it is only one HEGO throwing a code, not both. And they aren't that old.

I have also had coded 335 and 336 recently, which are linked to the DPFE.

Keep 'em coming.

TIA

 

[jaded93atx]

You could try swapping back the stock MAF and see if the codes go away, if not its not unheard of for O2s to fail prematurely. You could perform the bench test as on shotimes or (my preferred solution) check your connections and hook up a scan tool and see if on a "real time" scan the O2s are switching or one is being lazy.