2001 Pathfinder 3.5L V6 Rough idling and misfire

[catchin_zzz]

01 Pathfinder 3.5L V6 Manual TransmissionMilage 87,000 miles.

Having some major problems with my truck.Initially I had code P0153. Before I had time to fix the P0153 (O2 Sensor), another code showed up, P0505(Idling). Along with the P0505 came problems with acceleration and idling. I would stall when starting up the car cold and the car would not go over 3500 - 4000 RPM. The code P0300 shows up (Engine mis-fire). It would go up and then back down and then up and down repeatedly if I kept on the gas.

I took it to the dealer who advised that I replace the ignition coils and spark plugs. I did this and the idling and RPM problems are still there. It appears that the coil and plug change did nothing. The codes were cleared by the dealer and have not returned.

HELP!!!