94 T5 Code 433

[Clemens]

My 94 T5 has been throwing a CEL as of lately. I can clean it, but it comes back within a few miles.
The code is 433 on port A3 on the blinky box.
If I'm correct, this is the front O2 sensor.

My assumption is that because the code can be cleared, but returns, there really is an issue with the sensor or it's wiring.

At around the time the CEL comes on, the engine feels sluggish. Hard to say if the sluggyness is first, and the the CEL comes on, or if the CEL is first and the M4.3 cuts down power because of the code...

I have to mention that I put a Ferrita 2.5 inch catback exhaust on it in November and that ever since it has a tendency to pop loudly if letting off the gas.
Maybe this is related, not sure though.
The 02 sensor is 31 yesrs old afaik.

Any ideas are welcome.

[hausmeister]

I'd replace it, just because they also age.
Bad o2 sensor on mine caused massive fuel consumption and bad emissions, but I don't remember driveability issues. Might be something else, I'd still get a new sensor.

Don't think a catback alone (without downpipe) would cause issues. Don't know about the code, I'm only used the 1995+ codes, and that list seems different (A3 would be ABS)

[scot850]

When I went to high flow cats on my Toyota, I had to have the installers add an longer bung on the upstream O2 sensors to fool them due to the faster gas flow. It has worked well.

It could of course be a O2 sensor failing, but maybe check with the manufacturer is they recommend adding a thicker bung?

Neil