2005 5.3 1500 pickup multi cylinder misfar replaced intake gasket,coil,injector,and plug in cylinder 1&3 number 1 is missing the most also replaced oxygen sencer bank 1

Possible causes
- Faulty spark plug (s)
- Faulty ignition coil (s)
- Clogged or faulty fuel injector (s)
- Intake air leak
- Fuel injectors harness is open or shorted
- Fuel Injectors circuit poor electrical connection
- Ignition coils harness is open or shorted
- Ignition coils circuit poor electrical connection
- Insufficient cylinders compression
- Incorrect fuel pressure
What does this mean? Tech notes
The P0300 code means that a cylinder(s) is misfiring or is randomly misfiring. Start by checking for intake leaks, intake gaskets are common caused of multi-cylinder misfiring. If no leak are found the next step is to replace the spark plugs. If the problem persist more tests needs to be done to diagnose problem, see "Possible Causes"

Well its not exactly ignition or fuel injectors, since cylinder 6 in in the firing order. 1-8-4-3-6-5-7-2
Could be something with the intake again, or the pickup in the distributor. I suppose if you have the multi-port injection inside the plenium it could be some of the spider valves or lines.
You would need to know if those cylinders are firing, and if they have normal compression.

What engine do you have in your Nissan that has the misfire, how many cylinders and how many liters???

This could be bad fuel injectors or bad compression. Take a compression test, if its good then try switching the injectors to different cylinders to see if those cylinders misfire

CYLINDER 3 MISFIRING. MEANS NOT FIRING .CYLINDER 3 IS MISSING FIRE.COULD BE FAULTY OR DIRTY FUEL INJECTOR.YOU COULD HAVE BAD SPARK PLUG OR COIL AND WIRE.CLEAN FUEL INJECTORS CHANGE PLUGS AND COIL TO NUMBER 3 CYLINDER .WHEN YOU DO A LITTLE TUNE UP.THAT WAY YOU WILL KNOW IF YOU HAVE A MECHANICAL PROBLEM TO 3 CYLINDER LIKE LOW COMPRESSION.LEAKING INTAKE AT 3 CYLINDER OR BURNED OUT VALVE.

P0301 - Cylinder 1 Misfire Detected.

Causes:
- Improper spark plug at cylinder #1
- Insufficient compression at cylinder #1
- Incorrect fuel pressure
- The injector circuit is open or shorted at cylinder #1
- Fuel injector #1 may be faulty
- Intake air leak

Solutions:
- Perform Injector Service
- Replaced Spark Plug #1
- Replaced Injector #1
- Replaced Ignition Coil #1

P0303 - Cylinder 3 Misfire Detected.
Follow info from P0301.

P0316 - Misfire Occurred In The First 1,000 Engine Revolutions.

Causes:
- Damaged CKP sensor.
- Ignition System.
- Fuel Injectors
- Running out of fuel
- Fuel Quality
- Base engine
- Damaged Powertrain Control Module

Solutions:
Usually the P0316 is combine with a P03XX codes. The P03XX code indicates in which cylinder the misfire occurred.

P0300 - Random / Multiple Cylinder Misfire Detected

Possible Causes:
- Improper spark plug
- Insufficient compression
- Incorrect fuel pressure
- The injector circuit is open or shorted
- Fuel injectors may be faulty
- Intake air leak

Possible Solutions:
- Perform Injector Service
- Replaced Spark Plugs
- Replaced Injectors
- Replaced Ignition Coils

P0301- Cylinder Number 1 Misfire Detected

Possible Causes:
- Improper spark plug at cylinder #1
- Insufficient compression at cylinder #1
- Incorrect fuel pressure
- The injector circuit is open or shorted at cylinder #1
- Fuel injector #1 may be faulty
- Intake air leak at cylinder

Possible Solutions:
- Perform Injector Service
- Replaced Spark Plug #1
- Replaced Injector #1
- Replaced Ignition Coil #1

Most likely your issue is with cylinder number 1. Follow the info I have provided and you should be able to solve this issue.

did you take a compression check on these cylinders compare to 1 & 4, possible causes for such a symptom are as listed:damaged head gasket between 2 & 3, a cracked cylinder head between 2 & 3, faulty injectors, bad plug wires or coils(direct ignition), a warp cylinder head, intake or exhaust valve are losing compression,damage or sleeping piston rings.

Could only be a few things. The coil #1, Fuel injector #1, Stuck intake or exhaust valve, or blown head gasket allowing coolant into cylinder #1. Use a spark tester to check the spark coming out of cylindr #1 if checks good then ohm test the injector when it is warm. Check other injectors to compare. Do a compression test on cylinder #1 and test other cylinders to compare. If cylinder is low compression suspect valves and or head gasket. If compression is low then het a leak down tester to test if a valve is broke or sticking. On your sable i would suspect injector or coil most likely.

CYLINDER NUMBER 5 IS STANDING IN FRONT OF VECHICLE IT WILL BE THE 5 CYLINDER COUNTING FRONT TO THE BACK CYLINDERS IS IN ORDER 1 2 3 4 5 6 THAT YOUR CYLINDER ORDER. YOU HAVE A INLINE 6 CYLINDER ENGINE.YOUR MISS FIRE COULD BE THE COIL - SPARK PLUG - CLOGGED OR FAULTY FUEL INJECTOR. ALSO INTAKE MANIFOLD VACUUM LEAK OR SLIGHT HEAD GASKET LEAK WILL CAUSE MISFIRE.