88 bronco 2.9 hesitates under load?

my bronco hesitates under load when i climb a hill and accelerate to about half throttle.its 2.9 with 5 speed manual.
why is this
please help
thanks

When is the last time you changed the fuel filter? Take the fuel pressure test, see what you have. Otherwise check for vacume leaks, might be a bad MAP sensor.

My quess is to check the fuel filter.