Need to know how many connectors are on the PCM you have. The 97 5.2 harness will be early 3 connector JTEC, where the 03 may be JTEC, but a newer version. I am not sure that you can use the 03 PCM with the 97 5.2 and harness. Call your connection in Oregon and see what they say. If they say they can make it work, go for it.
