IAC valve? '97 S-10

I have a 97 S10 (4.3, 4WD, 5-spd). When I take it out of gear and coast, the RPMs rise and fluctuate rather than dropping down to an idle. This will continue until I bring the vehicle to a complete stop. I pulled the IAC and made sure the pintle was set to 28mm. It worked for a while, but now the problem is back. Any ideas? Thanks.

check the tps sensor. also check to see that you dont have any vacuum leaks.

Did you clean the iac and the hole it fits into with carb or TB cleaner?