Hi all. I have been reading through the forum for over a week now but still unsure as to what to do....

Basically I have an issue with kangerooing...the cell light is on and the diagnosis machine said 'cat below threshold and lean. This was when the car had a decat with o2 sensor present, I have now put the cat back on with the o2 sensor still present but the cell light is still on and says the same.
Basically the car is sometimes OK but frequently drives really bad.
When ignition turn on the car is OK for a few minutes then soon after the idle fluctuations up and down then when driven the car is very jumpy below 2k rpm but is OK over this rpm and in higher gears.
I thought putting the cat back in with sensor present would sort it out..but no....please help lads its driving me crazy and only owned her a couple of weeks and haven't had a chance to enjoy it yet!
I have considered that the o2 sensor in the cat needs replacing...but how can I tell that its not the other o2 sensor in the manifold instead...? Don't want to have to replace both. I read on here that the o2 sensor in the cat is only the secondary sensor and shouldnt create a cell error light or kangerooing issues...

Please help guys...Thank you

Rich

 

Please assist its driving me crazy not being able to enjoy my s2k!

 

Anyone?

 

Did you reset the ECU? Try that and see if the CEL comes back...if it does check the code. It is more than likely that rear sensor but the code itself is necessary to tell.

 

Thanks. The code is Po434

 

P0434 Heated Catalyst Temperature Below Threshold (Bank 2)

Seems to be the after cat sensor...reset the ECU and see if the CEL comes back. If it does, try replacing the sensor (shouldn't be too expensive or time intensive).

 

The sensor in the manifold? Despite it mentioning the cat in the cell error?

 

No, I believe the 2nd bank oxygen sensor is the one that is located to sniff within the cat. It should be the sensor you screwed into the cat when you put it back on. It could have burned out over time if it wasn't up high enough from the exhaust while sitting in the test pipe.

The manifold oxygen sensor is bank 1 I believe.

 

Awesome thanks mate. A guy on the under the Hood section mentioned that the sensor in the cat cannot produce fueling issues as the manifold is the main one.....and said to test them both....how to test them I.wonder..

 

If you have an OBDII scanner you could verify the voltages on both of them are performing the same (the post-cat sensor will have a very-slightly different reading), but while idling they should be going up and down in a kind of sinusoidal pattern.