34MPG in a 2002 Grand Cherokee diesel

[cRiPpLe_rOoStEr]

Originally Posted by Logic

I think most modern cars' ECU's simply compensate for whatever mix is in the tank since the advent of E85.

Might throw some error codes and turn the CEL on, but it won't kill the engine. As long as it has an O2 sensor, it's presumably safe...