RID3R

Im stumped and wondering if anyone else has encountered the same problem as i have encountered. I have a 2002 i35 auto with 204K that is in Limp mode and cant solve it. Car started to over heat from going uphill with the AC on and outside temps where in the 90's. There are no codes in even with an OBDII reader. On flat ground 25 MPH is the limit and uphill starts to lose speed to 5 MPH, in park 3k RPM and hits limit.
MAF and Cam postition sensors replaced, checked fuses and relays, all good.
Both pre-cats gutted, new O2 sensors. checked knock sensor and coolant temp sensor by unplugging and car threw CEL right away so they work.
If anyone has had this problem please let me know only thing left is maybe dead ECU but from my tests it seams to be working.