i may have my problem fixed but not sure
 

i have a 94 silverado half ton 4wd extcab 5.7lv8 standard 4x4 package
i think i have fixed my problem but wont be sure until i replace the part
the truck will at idle or park or stoped drop from the normal 1000 to around 400 to 500 rpm
i have checked the fuel pressure its at where it should be both running and with the key on but not running
also replaced the fuel filter and the coil also new wires
i took of my idle air control valve wires and drove around the block abotu 6 times the truck runs great with it disconected then i put it back on it runs like crap
so that leads me to believe the idle air control valve is bad
if that dont fix it where do i need to go from there
as i am on a fixed budget
and i hope that my timming isnt off but i havent checked that yet
so if the idle air control valve dont fix it what to do
also when driving it bogs down then when i give it gas it runs ok