Fuel filter replaced, won't idle, egr?

SOURCE: 1990 jeep cherokee laredo 4.0 liter 4x4

check the ballest see if that works

SOURCE: PO171 OBD-II Trouble Code " System Lean To Bank 1

Check PCV valve and be sure it is not stuck open.  Check for vacuum leak at intake manifold.  

SOURCE: High Hydrocarbons cant pass emmissions test

If you changed the battery or it went dead before your test ,it reset you history you will have to drive it a couple of weeks to update you emission control module then have it retested

SOURCE: 1993 Jeep Grande Cherokee wants to stall

DONT BE CHEAP IF IT NEEDS IT DO IT JUST MY ADVICE JEEP ARE DIE HARD

SOURCE: Misfire problem... engine stumbles at idle

my jeep was misfiring and i changed the same parts you changed.... When you changed your crank sensor, did you get parts from the dealer? if not u should trying changing the crank senor part from tne dealer. After market parts do not work good on Jeeps I had to learn the hard way..