I bought an 08 G35x that had been overheated and had warped or cracked the head so I replaced with a 08 long block. Installed it and is started right up, sounded good and drove but it would not shut off. I had to disconnect the alternator wire from the battery to kill the motor. Now when you try to start it most of the time nothing happens however every once in a while it will have a delayed random start but still will not shut off on its own. It shows a U1000 code, the yellow key light comes on and the red car with the key in it flashes on the dash. You also have to open and close door to get it go into accessory mode once you have pushed the start button. I'm thinking some sort of problem with the communication with the security system? I have checked grounds and had the fob programmed. Is their reprogramming that needs to be done to make it work with the new motor? Car did start and run with none of these issues before replacing motor. No Infinity dealer in my area, I will greatly appreciate any help. Thanks