You can only go as late as GM went with that PCM, 2004 used a different PCM, as did 2003 trucks.Originally Posted by 87gmc
For your 5.3L truck I think 2002 is as late as you can go.
I've just finished off the 2002 O.S's and they should be posted up for download in about 12hrs time (it's midnight here!!).
Cheers,
Ross