6.1 Swap Won't Rev Past 3K HELLLLPPPPP!!!

The thing is this pcm only has three plugs. The fourth one is blank. The last two we got from ben at plum floored all had four connectors. The pcm in the car came from street and performance and was claimed to be a plug and play pcm. Well it plugged right in and the car runs perfect, besides the fact that it wont rev over 3 grandish. It doesnt have an egr code, just the evap code. I really have a feeling that the wiring harness is the culprit, but trying to get in contact with the guy that built it is impossible at this point. The douche bag that sold it to us wont return any emails or phone calls. At first I thought it had something to do with the TRS signal wire, but after grounding it straight from the pcm the same problem still exists.