Just giving a heads up if anybody ever has any similar problems. My truck started idling irregularly. Rpms would jump between 500 and 1000 rpms. Also when going from a stop, the truck would not accelerate smoothly. So I took it to the dealership. They said that the fuel mixture was going from lean to rich and back just sitting still. They said they have never seen it before. The Nissan techline did not know what it was either. It took the dealership 3 days to figure out that the intake was cracked and to replace it. It has been running great ever since.