In this revision to enter first person view in a car, cycle the views with the game view button or key until it comes up.
To enter first person on foot double tap the game view button or key quickly while on foot.
This is an ASI mod so needs an ASI loader to function.

NEW: V1.22

Aiming offsets adjusted to be more accurate.
Optional first person view for..
Drive By, Melee, Cover and Aiming. INI settings explained below.
Transition screen flickers eliminated.
Smoother framerate in vehicles.
Mouse users can now once again change to toggle aim mode and first person aiming will work.
Altered the double tap time to enter firstperson on foot to slightly longer.
Changed the movement style to a more first person type. e.g. with mouse A and D always strafe.
Rolling cover dives and jumping to a roll now rotate the cameras pitch 360° during the animation.
Adjusted cruise control to be less sensitive to disabling conditions.