DONT use pliers ! you could damage the stepper motor that works the
valve.
turn the thing a quarter turn and run some wire thru the bolt holes...
loop the wire thru the bolt holes and then back together...kinda like
a handle on a basket...the PULL UP on the wire (this allows you to
pull STRAIGHT up w/ a continuous even pressure on both sides...it
pop right out.
when you clean it you should be VERY careful not to get any "cleaner"
or soot in the two holes that are in the bottom of the "motor" housing.
when you clean it you should replace the "silver" base gasket AND the
two o-rings...becareful not to BED the valve when opening it...do NOT
spray carb cleaner down the housing "hole" (on the engine side)...use
a brush and a vacuum to "knock" the soot loose and SUCK IT OUT
w/ the vacuum.
this might help:
EGR CLEANING &
EGR SERVICING