There is only one file type that uses the .MF4 extension:
ASAM Measurement Data Format File
An MF4 file is a data file saved in version 4 of the ASAM Measurement Data Format (MDF 4), which is a standard file format used by the automotive industry for storing measurement data, most commonly sensor data from an engine control unit (ECU). It contains raw measurement data recorded from a measurement and the metadata necessary to interpret the raw data.
MDF is developed by Vector and was originally released in 1991 as MDF 2.0. It soon became the standard format used in the automotive industry to store measurement data in regards to development, testing, and calibration of vehicles. MDF 3.0 was released in 2002, which uses the .MDF file extension. In 2008, an ASAM group revised the MDF standard and released ASAM MDF 4.0 in 2009, then ASAM MDF 4.1 in 2012.
Updated: June 9, 2017