EGR code cant fix

i get this code after driving to operating temp. i got 3 egr solenoids and tried all three and still ckeck engine light comes on code 32...so then i took the egr valve off and cleaned it. it moves in and out when diaphram is depressed, there is vacuum going to the egr solenoid but no evidence its pulling the valve when its suppose too. also when i press the diaphram on the egr valve while its running it makes no difference in the way it runs,
i tried this on my 88 cavalier and it ran rough as hell, could the TBI EGR port be stopped up in the throttle body? stumped on what to try next or do...
the vehichle in question is 1988 s-10 blazer 4.3L Auto tranny 4WD.
one more thing, when the check engine light comes on it stays on untill the truck is cut off and restarted, then a few miles later it comes on again and stays on....

There is a good chance that either the EGR exhaust passage or EGR intake passages are blocked or obstructed with carbon and coking. You can remove the EGR valve and run a still wire (coat hanger) through the passages to help clear obstructions.