if you have a smartphone (android or Iphone) you can purchase an app called Torque....There's a free version and a pay version..its $5.99...you'll want that one.
go on ebay and purchase one of these:
http://cgi.ebay.com/ebaymotors/Bluet...motiveQ5fTools
for $25.00 you can do just about everything you need including some other very cool features. its like a Gtech pro with the ability to read scan and clear codes...IT also displays real time data with gauges etc. data logging is also available i believe.