... but does anyone know what they are? The wiring to the sensors on mine seems a bit crusty and has broken right at the plug on both sides. I've bodged them back together but I'm considering just making new cables up and taking them straight back to the ECU. But first, I need to know what kind of plug I'm buying!

Put a picture up so I can be sure...

But I believe GEMS sensors used a 4 way econoseal connector for the O2 sensors... Thor used something different.. possibly Sumitomo from memory.

The econoseal connectors are fairly easy to get hold of.. again, I believe they are the 040 series.

Hope this helps,
Marty

Not sure they are, they are a strange square shaped thing. They may use econoseal pins and sockets but not the housings. I'd be inclined to change the connectors for supaseal or similar if the originals are getting a bit crusty. One of mine may well be the same, I get a logged lambda heater fault on one, despite having changed the sensor, but as it isn't used 99.5% of the time, I've not done anything about it.

I’ll have a dig about in garage, I had a pair of lambdas for a gems, no promises but if I find and anyone wants there welcome to them..

Ahh, looking at the O2 sensors on Island 4x4 the standard econoseals are used from '95-97... '97 - 00 do use something else, and no idea what they are!

I'll have to look at my '98 the next time I'm at the workshop and see if I can identify them.. my guess is still a Tyco/Amphenol connector of some description

It's even weirder than that. Up to about 96-97 they used black plugs, 97-Thor used grey plugs that don't fit black plugs, and Thor onwards jused something different.

I think the black plug, grey plug was just to make identifying what you had easier. If someone wanted a new sensor but wasn't able to supply a VIN number, it would be easier just to ask what colour plugs it has.