Before you start, hopefully you have radio security code.
Try this, clean battery clamps and battery posts and other end of cables.
Check mechanical condition of cables and replace with min 1 AWG if questionable.
Take a battery charger and place charger function switches to 'START'
If engine starts up, this may mean battery not charged to full capacity and/or battery too small capacity.

 

A couple thoughts.

O2 sensors are maintenance items and should be replaced about every 100,000 miles. The volt meter can check if a O2 sensors is bad but it will not tell you if it is accurate. The test to check O2 accuracy will cost more then you installing O2's. If you have an issue with an entire side of an engine you either have an O2 sensor issue or a plugged fuel rail. There are not many things that would effect one side of the engine.

Did you happen to take pictures of the plugs? Reading plugs is something best left to guys that have seen hundreds or thousands of plugs.

Have you done a fuel pressure test?

Started shimming should not be trial and error. There is a shim setting procedure that requires a drill bit as a gage. It should be in the manual.

 

The pic is 2 of the plugs. The left plug came from the left of the engine and right right. All the left plugs looked the same or close. The right plugs looked more dry

I checked the fuel pressure before pretty much anything was done. Had really no fuel pressure then. I'll get it checked again.

I tried finding the place where i can check the starter and flywheel but I can barely find it since there's like no space in these engines from top to bottom. Was hell changing the plugs.

 

Got a pic of the flexplate. Idk if its damaged. I should have took notice of all the dirt buildup. Whoever had it let the dirt under the hood buildup bad to where it was inbetween where the starter goes. Cleaned it and will see how she does

There is no way to measure the gap. The other side is blocked off :/. Maybe the reason why there were to shims when i took it off.

 

Left side is fuel fouled. The right one is normal or maybe slightly lean.

This is when 2 new O2 sensors and a scan tool would come in real handy. This the fuel fouled plugs you know that O2 is done for. You are not getting a complete burn on the plug and the same crap that is on the plug is on the O2.

After you install new O2s you could watch the fuel mixture. If the rich side get better the harder you drive it is likely a small vacuum leak or some dripping injectors. If it get worse it a fuel pressure/volume issue on something in one of the sensors.

 

Your flex plate is fine but it showing signs of a recent mis-adjusted starter but the wear pattern is very small. You need to remove the dust cover to get better access. You don't need to keep telling us how hard these cars are to work on. There are very few parts of this car I have not had a part at least once if not 5 times. I have owned 3 of them and the V8s have less room then the V6s.

Have you checked the service manual for instruction on setting the starter? They do not give instructions that are not possible. Also Youtube is a good resource for how to videos.

 

do a fuel pressure test. low fuel pressure can cause a rich condition.

 

A pic of the back part behind the starter. Idk if that part is the dust cover but looks like I'd have to drop the transmission pan or worst, transmission.


I followed this vid. Other starter had no shims nor did they put one on the vid so I'm not putting any on.

Gonna buy the voltmeter tonight at work do some testing in the morning.

 

Tested all o2s. Idk if the number of the continuity matters but they all had it. Weird enough watched a vid and said test the black wires. Both my new and olds got black and grey but the white ones read back.

 

Tried another fuel pump under warranty but problem remains. Guess I'ma try the camshaft. Not too much for it. Wouldn't think it'd cause a bad start though