Have been wanting something like this for a long time. Tried an OBD-II reader from Sparkfun but it was sort of flakey ( no knock on Sparkfun, I did not really p

Have been wanting something like this for a long time. Tried an OBD-II reader from Sparkfun but it was sort of flakey ( no knock on Sparkfun, I did not really pursuer the trouble). any one use one of these?