Spark wires/Coil ?????

Your spark plug wires go to coils, coils sit on top of ignition module.You have two crank sensors, if crank sensor issue, check the 7x crank sensor, on back side of engine block, down low, two wire connector, wire colors, yellow and purple.

It does not have spark plug wires, each cylinder has a separate ignition coil. It is referred to as coil over plug ignition. It would be a better idea to state what problem you are having.

Check crank and cam sensor.

rather than rely on that check the plug on an exposed metal surface, if you have a good spark it is not the electrical system at
all. Work backwards from the plug to identify the fault if the spark is not very good.If they are all okay check the compression on that cylinder. Once these procedures are completed you should know where the problem lies. could be worn bore, rings or a valve issue

Disconnect one of the battery cables for 5 min. Reattach it and tighten manually. This resets the ECM and possibly will allow starting. Disconnect a plug wire and get someone into the drivers seat and attempt to start. Hold plug wire close to spark plug and see if there's a spark. If no spark, either the battery is bad or COIL.

It is usually coming from the spark plug wires( leak spark). Spark to ground or piece of metal.
To find out exactly take an empty spray bottle fill her up with water and add 2 tablespoons of salt. With the engine running a light spray of the mix on spark plug wires you will see the spark leak and proof the spark plug wires have a defect. if so replace all spark plug wires that should solve your problem.

Hope it helps.

Inspection

Inspect for the correct routing of the spark plug wires. Improper routing may cause cross-firing. Inspect each wire for any signs of cranks or splits in the wire. Inspect each plug wire boot for tearing, piercing, arcing, carbon tracking or a corroded terminal.
If there is any corrosion, carbon tracking or arcing indicated on a plug wire boot or terminal, both the plug wire and component it was connected to should be replaced.

Removal & Installation

3.5L Engine

1. Before servicing the vehicle, refer to the Precautions Section.
2. Remove the left side spark plug wires from the spark plugs.
3. Remove the left side plug wires from the retaining clips.
4. Rotate the engine for access as follows:
   1. Set the parking brake.
   2. Shift the transaxle into neutral.
   3. Remove the engine mount strut bolts. Swing the engine mount struts aside.
   4. Install the Engine Tilt Strap J-41131.
   5. Pull on the engine in order to rotate the engine forward.
   6. Tighten the strap.
   
   
5. Remove the right side spark plug wires from the spark plugs.
6. Remove the plug wires from the retaining clip.
7. Remove the spark wires from the ignition coils.
8. Remove the plug wire assembly from the engine.
   NOTE If you are replacing the spark plug wires, the spark plug wire conduit and retaining clips should be transferred to the replacement wires.
   

To install:

1. Install the right side plug wires to the ignition coils and then the spark plugs.
2. Install the spark plug wires to the retaining clip.
3. Rotate the engine back to the original position.
4. Install the left side spark plug wires to the ignition coils and then to the spark plugs.
5. Install the spark plug wires to the retaining clips.

3.9L Engine

1. Before servicing the vehicle, refer to the Precautions Section.
2. Remove the intake manifold cover.
3. Remove the left side spark plug wires as follows:
   1. Disconnect the left side spark plug wires from the spark plugs.
   2. Disconnect the left side spark plug wires from the ignition coil.
   3. Remove the left side spark plug wire clips from the intake manifold and heater inlet and outlet pipe.
   4. Remove the left side spark plug wire assembly.
   
   
4. If removing the right side spark plug wires, the engine must be rotated for access as follows:
   1. Set the parking brake.
   2. Shift the transaxle into neutral.
   3. Remove the engine mount strut bolts. Swing the engine mount struts aside.
   4. Install the Engine Tilt Strap J-41131.
   5. Pull on the engine in order to rotate the engine forward.
   6. Tighten the strap.
   
   
5. After rotating the engine, remove the right side spark plug wires as follows:
   1. Disconnect the right side spark plug wires from the spark plugs and ignition coil.
   
   
6. Remove the right side spark plug wire clip from the ignition coil bracket.
7. Remove the right side spark plug wire assembly.

To install:

1. Install the spark plug wire assembly.
2. Install the right side spark plug wire clip at the ignition coil bracket.
3. Connect the plug wires to the ignition coil and spark plugs.
4. If the engine was rotated for access, return the engine to the original position.
5. The remainder of the installation is the reverse order of removal.

the firing order is 123456 pretty easy, but i think what you want is spark plug location on the coil packs, so lets start with cylinder placement. starting at the front of the engine the end with the belt the three cylinders closest to the radiator are 2 4 6 the cylinders at the back of the engine are 1 3 5 the spark plug wire location is from the front of the coil pack( fount of engine ) 1 4 6 3 2 5......HAVE FUN

Spark plugs,wires and injectors, have nothing to do with your problem

PO303 is a misfire on cylinder #3
You may have an individual cylinder coil for that cyl or a coil pack for
several cyl,don't know the engine you have.

You may also have other issues that are causing the shaking

The spark plugs are located below the 'coil pack' in a hollow tube in the head. You must remove the spark coil retaining screw to access the removal of the soark coil. The reoval with expose the spark plug at the bottom of the hollow tube in the head. The total spark coil is about 6-7" long and when it comes out that is when you will see the spark plug at the bottom of that tube. It sounds difficult to find but once you know it is easy. There is no coil wire(typical spark plug wire) attached to the spark coil. It is fed by a special connector on the side of the spark coil. Look on the side that has the least number of hoses and equipment in the way. Find the top of the spark coil (about 1-3/4-2" in dia) with a wire connected on the side. There is a single small metric bolt holding the spark coil in place. It will not come out until that screw is removed. I hope that this helps.