Scangauge II

[HiTek21]

Link

This is a pretty neat little gadget to have in the car. It plugs directly into your ODBII Port and it can do various function. It also doubles as an ODB II scanner which can tell you what code your check engine light is throwing.

 

[P0pinjay]

Dashhawk

Bit more expensive but offers some of the same features...plus others that the SCII does not...data logging, 0-60 times, etc.

Unfortunately, I bought one of these a few months ago under the mistaken impression that instantaneous MPG was one of the features already present. Luckily, they have a pretty communicative programming staff and they say that instantaneous MPG should be coming in a firmware update shortly.

 

[shabby]

I got the dashhawk too, with the next update it will also show instantaneous hp/trq. Its well worth the extra cash over the scangauge which seems a bit primative.
The product suppport for the dashhawk is top notch, ask for a feature and you will recieve it.

The downside is that it only works on newer cars that are CAN compliant.