Just pulled this code off. Does this mean my cat has gone south? The code reads as "catalyst effiency below threshold (bank 2)". If I'm right, has anyone changed their own cat? Is it a bear to do?

Thanks,

Bill

 

This code is posted at the end of an OBD-II "drive cycle", where the post-catalyst oxygen sensor was found to be switching excessively, when compared to the pre-catalyst oxygen sensor. This means that the catalyst is not succeeding in treating all of the HC/CO/NOx produced by the engine.

However, a catalyst replacement is expensive, and you should rule out other possibilities first. For example, Ford found that the 1996 model year vehicles were overly sensitive, and tended to post these codes too aggresively. There as a Ford TSB that recommends that the first service action when seeing one of these codes is to upgrade the PCM to the latest calibration (the programming is downloaded through a tester to flash memory within your existing PCM).

A tired (high miles) front oxygen sensor can lead to flagging of this code. So can worn spark plugs or bad plug wires. A contaminated MAF sensor can lead to erratic mixture control as well.

If the oxygen sensors are high miles (>75K), I recommend replacing all of them. Same story with the spark plugs and wires. Consider cleaning (VERY CAREFULLY) the MAF sensor. (Use only spray on contact cleaner, do not touch it with anything).

If you have tended to all these details, try clearing the code (use a scanner or disconnect the battery). If the code comes back within a week or so, go to the dealer and get the PCM calibration checked and upgraded if needed, and clear the code again. If it then comes back yet again, it may be time for a new cat. Catalytic converters are much cheaper from the aftermarket (CATCO) than from the dealer. There may be some restrictions on the use of aftermarket cats in your area -- there are such limitations in California.

 

I should have said that it is a 98 sport sohc, 62k miles. I replaced the plugs with Bosch platinums and wires with motorcraft brand. Also put in a K&N box filter. The gas milage has gotten pretty bad and it does have some hesitation. My plan is to change out the plugs again (NGK Tr55's?) and put in a new set of wires. I bought the last set from a forum member who said that they were used for only a few thousand miles. Who knows about that.

Any recommendations for plugs and wires?

I will reset the code and see what happens.

Bill

 

The error code states "bank 2". Is that side specific? Meaning driver or passanger side?

 

On a different vehicle in a different forum a different person reported that bank 2 was the driver side.

If you want to be sure, disconnect the thing. Run the vehicle for a while. The computer should complain with a different code. The code will be something like "bank x always lean", but should have similar specificity (bank 2 vs bank 1). The bank assignment should be consistent from one code to the next, for a vehicle of a given type.