[John S]

I am throwing a po300 misfire code still.

I have changed plugs coils and rear valve cover cause 1 plug seal was bad. Engine light went out for a day then came back on with the same code. The car is running good no smoke not sluggish starts alittle hard, rpms idle around 800 when its warmed up no issues while driving either. what are my options to check.

 

[PoManzPathy]

Have to scan it to see desired and actual fuel trims and see how the O2 sensors are responding, the MAF sensor is responding, etc. It's tough these days. Not only do you need someone with the right $$$$ diagnostic equipment along with the monthly subscription services, they need the know how on how to decipher data as opposed to just keep winging parts at a problem to hope the problem stops.

 

[John S]

Thank you for the info....its going to be my last resort bringing it in some where.. i dont mind trouble shooting problems i like doing it. The other problem i have a rattle noise coming from the left side of the motor goes on when cold goes away when warmed up.

 

[PoManzPathy]

Thank you for the info....its going to be my last resort bringing it in some where.. i dont mind trouble shooting problems i like doing it. The other problem i have a rattle noise coming from the left side of the motor goes on when cold goes away when warmed up.

Left side as sitting in the driver's seat or the other left?

Common to have exhaust heat shield rattles and engine ping / detonation from these engines.

Yet another thing to add to the pile for you is, if yours is 4x4, you need to change out that transfer case gear oil ASAP. Not a bad idea to do the rear diff gear oil too, but the more critical and less tolerant box is the T-case. It's a PITA w/out a lift, but doable.

...and the CVT fluid..

 

[John S]

Its on the passenger side

 

[PoManzPathy]

Its on the passenger side

That would be the right hand side of the vehicle then. That's were all the rotating, belt driven elements are and where the transfer case is. Rattling can also be the radiator cooling fans on their way out. Super common. The bearings/bushings wear out on the motors and the plastic fans wobble and hit the shroud. The noise can come/go.

 

[John S]

Thank you for all the info it helps. By any chance do you know how to get any engine diagrams or repair manuals.

 

[PoManzPathy]

Thank you for all the info it helps. By any chance do you know how to get any engine diagrams or repair manuals.

No problem. You won't find a better R52 or R53 site then this one.

In terms of free online service manuals, unfortunately all I know of is here and it's only up to the 2016 Pathfinder. Still some relevant info for 2017-2020. https://www.nicoclub.com/nissan-service-manuals