failing cat?

[5ktq]

The last three days in a row, my car has thrown a code for "catalyst efficiency too low". ( I forget the exact number for that). No other codes.

All three times, condition and timing were identical.

-Start car, let it idle a few minutes, temperature is just above freezing in the morning here.
-Drive couple minutes down residential (30MPH) streets.
-Get on to freeway ramp, speed up to 65mph, merge
-Put it in fifth, decel slightly, cruise for less than a minute... bam, engine is light on.

I then clear the code when I get to work, drive around town at lunch and on the way home from work, no codes, until I repeat the process the next day.
traffic is worse on the way home so its more like 50mph then, and there is less freeway (different route).




Now, if the cat actually was dying would it even throw a code that soon? I think rear O2 sensor is more likely?
Car has 95k mi, both oxygen sensors and cat look to be original.

[MetalMan]

Rear O2 sensor is a lot cheaper and easier to replace, and with 95k / 11+ years it's probably not a bad idea anyways.
Stock cat should last a lot longer than 95k miles unless it was subjected to poor conditions (i.e. engine running rich for long period of time, excess oil in exhaust)

[5ktq]

Yeah, that was my line of thought too.

So the front is a wideband, and the rear sensor is a normal 4 wire, right? So I can splice in whatever the cheapest bosch 4 wire is then. Amazon.ca has a 4-wire bosch for a land rover for like $14 US... might try that. They're giving them away.