Most cars just have dummy lights, it is nice to have actual numbers.

Engine Coolant Temperature
Fuel Pressure
Air Intake Temperature
Oxygen sensor voltage (that is actually useful on my car)
Battery voltage
Throttle position (handy to stay in the 'sweet spot' when trying to maximize MPG)
MPG data both instantaneous and long term(many modern cars now have, but that has become common only recently)

Dozens of others as well.

Having feedback on instantaneous MPG is a great tool to save money. I'd argue that that feature alone would pay for the gauge in a short period of time for most drivers due to fuel savings from adjusting how they drive.

F a vacuum leak. I will gladly pay someone to look for that stuff.
I would love to get more familiar with my car though. At the present I usually know what is wrong with it before I bring it in to my mechanic, I just don't necessarily have the time, space, tools, or courage to try and fix it on my own.

 

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most cars give out that info.
except from O2 sensor. which o2 sensor does it give you? all of them? do you really even know what youre looking at with that info or is it just a fancy gauge you show off to yer buddies to try and look smart and stuff?

also, tps info is only what your gas pedal is doing. with drive by wire you dont control the throttle anymore, the computer does. as a result TPS /= actual throttle angle anymore.


just about all cars now adays have driver informatin centers that give you read outs of everything from coolant temp to tire pressure, including MPG current, long term, estimated, etc...

 

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