Anyone using propane in the new 2012 lml engines yet,as a backup from diesel.

Ive not heard of anybody with a kit for it

From what ive seen most companies that made propane injection have been backing out of production of those systems

Check out CNG , you might have more luck finding a kit.

You looking for extra power or to run strictly on propane? If you want more power/mpg it seems like the trend has moved towards water/meth injection.