My Pinto engine struggles to tick over and when throttling the engine splutters and tries to die.

Very must much like the timing is miles out, but it's not.

Was running fine.

I suspected the O2 sensor so disconnected it and the engine runs fine.

My question is is this a good indication the sensor needs replacing or could this be masking the real issue?

I don't think the sensor will come out without being butchered so want to be sure before I attempt to remove it.

Thanks Po79.

If it runs fine without the sensor connected something must be wrong with either the sensor or something the sensor talks to.

What EFi are you running? How does the ecu get the signal? direct or via a wideband controller?

I always thought the mixture only trims a relatively small amount based on O2 sensor feedback and would tend towards rich if it gets no signal at all. When I last had one fail it was just like having it disconnected and it ran a bit rich but not too bad. Other than a slightly sooty exhaust you wouldn't know it was rich.