Sorry, I think I posted in the wrong area last time but...

I've been using the torque app for my Nexus 4 for a while now. Love it. The bluetooth cheapo straight from China ELM327 dongle has been a bit temperamental, but works.

Just wondering though, would it be possible to use the dongle/phone combo as a piggyback on the ECU for tuning?

Not talking about flashing the ECU, but a "simple" piggyback.

would it be possible to make an app for that?

Also... I've noticed that my fuel economy has gone up since I've just left the bluetooth dongle plugged in all the time (in the OBD2 port). About 2-3mpg (noticable. I calculate every time I fill up) and it feels like v-tech is not kicking in as hard anymore... Very odd... (maybe it's just the weather or good gas, but I'm fueling up at the same place and driving the same roads i usually drive)
It's probably just in my head...