First I don't know what the "CTS" is, but because of your statement about the fuel pressure leakdown I'll toss out another thought. I was having intermittent starting issues with my '05 Jeep, and I changed just about every sensor it had - Crank Position, Cam Position, Throttle Position and finally took it to a buddy of mine who had a repair shop. After chasing things for most of a day he found that three of the six injectors were leaking down, bleeding off pressure and wouldn't hold against the pump head. I told him to change them all, and it was like a different engine. Wondering if perhaps you've got some bad injectors?