Hi,
mpguino can show RPM when it is programmed to to so - it can get it from injector signal
mpguino is best thing for lean burn - it measures directly from injector. Yu probably notice it from instant mileage reading when it is in lean burn mode - should be much more economical reading.
I have mpguino calibrated in my car and it is accurate - under 1% error. (when taking 60L diesel, pump and mpguino readings difference is under 0.5L)
Check my signature for mpguino web link.
Meelis