Only use the isuzu part! The one that autozone sells will not last.
I purchased an isuzu egr from ebay from an isuzu dealer. It actually looked like an isuzu sticker was pasted over the top of a GM sticker. This egr has been in my trooper for 2 years now and the dreaded CEL has not come back. I tried 3 autozone units and the lasted about 6 months each.
My port was plugged when the OEM unit went out on me. I cleaned it up then and have kept it clean, so I know the autozone units were not failing due to plugged ports.

1987 trooper LS.'94 3.2, SAS,35's , lots of dents and rust. Now, improved, with more dents.
1995 trooper LS. Wife won't let me improve this one.
1996 trooper. I'll need something to modify when the '87 finally rusts away.