I have a wideband lamdba sensor I would like to use can I buy a gauge to read the sensor outputs or would I have to buy a complete kit.
You have to buy a controller to drive the sensor (e.g the Innovate LC1), you can get them without the sensor to save some cash. I don't know of any gauges with built-in controllers but there may be some.
They do exist, but ain't cheap... usually a bit less than a proper controler with digital, narrow and wideband like an LC-1... If you plan just run a gauge, than it's fine, but if you want to go down the loggin route in a future, go to the controller
I,ve just bought one of these
AEM Kit
It looks very comprehensive, guage, controller, lambda, all wiring and not stupid expensive.
Nick