I have a 1999 Ford F150 4x4 that originally had a 4.6L that had two dead cylinders. I recently installed a 5.4L and tried installing a 5.4L PCM, engine harness, COPS, etc. I found out the hard way that the intermediate wiring harness/fuse panel is incompatible, so I went back tot he 4.6L PCM and Harness. Like everyone said, it seems to be running fine and I know many has gone this route.

Was wondering how Ford puts a 5.4L tune on a 4.6L PCM or if it's really been done? I know there's different programmers, and most of them are $399 and greater. I have access to Ford IDS and VCM2 and was curious to know if someone has ever loaded a 5.4L PCM configuration/calibration and installed it on a 4.6L PCM?