Engine studders alot when in Idle. Driving up hills leads to a massive engine shake due to less than 2 cylinders not firing. Sometimes will drive normal, that's how you know it's an electrical problem.
Some Nissans with the 2.5 have multiple ignition coil failures.
The reason is the negative battery cable is corroded at the mounting at the bell housing on the transmission.
the solution is to replace the entire negative cable with a factory upgraded cable and replace the coils as well.