I log with the various Android OBD2 apps - Car Scanner - they are good enough and usually free. I'm sure the Iphone has them, too. I have also picked up a VX Diag VCX Nano J2534 device on a USB cable that is also a bi-directional scanner / logger / Tech2 emulator and lashes up with PCM Hammer for four times faster PCM reading and writing.

Rick