I just finished putting my motor from my 87 in my 91. The motor ran fine in the 87 but now when I try to boost it cuts out. I used the wiring harness from the 91, ECU, and all the sensors for the 91. I installed the HKS F-CON in the 91 with the right wiring harness and a HKS FCD type-k. Everything has been wired up correctly. I thought if I hooked up the PBs it would run different. It runs like this with or without the PBs. There are no boost leaks, no exhaust leaks, and no oil leaks. The car starts up fine, Idles fine, and everything else until it starts to boost. I have never had this problem. Could somebody help me.