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I am new to this forum so I sincerely apologise in advance if I format anything wrong.
66k miles 2017 V6 supercharged convertible
My Jaguar had an engine light for a while, i had a bad gas cap so I had just assumed it was an evap leak and ignored it - turns out cylinder 4 had a misfire and I found out when I was doing a pull and the flashing engine light came on.
Replaced the spark plug and ignition coil on cylinder 4, (spark plug was oem new) (ignition coil oem but used) engine light went away on its own without having to clear codes. The engine light would come on back on its own flash then go away so I was very confused on what was going on. A friend advised me to try using catalytic converter cleaner - I did and heard some weird sputtering but for now its gone away.
When my dad changed out the spark plug and ignition coil earlier and he unfortunately spilled coolant on the bank. He claims it didn't get anywhere important but we don't know anything if that's even what's causing the issue. We tried contact cleaner on the entire bank of connectors, the car behaved somewhat better but the same thing with the engine light coming on, coming off and then coming on permanently. When scanned it came up as a misfire on cylinders 4, 5 , 6. However, I successfully did pulls without the engine light coming on.
I'm really at my wits end with this car... This all happened on my 21nd birthday . Already spent upwards of a couple thousand on an entirely new coolant system to fix a leak.
Our next step is going to try and replace all the ignition coils and spark plugs as our theory is we put a new one that had a different level of wear that could be causing an issue. Budget won't allow me a totally brand new OEM version so I am trying out a well reviewed one so it's in the post. We think it could be a fuel pump but we aren't really sure or a vacuum leak and have been mostly going off what AI has been telling us. Any guidance would be sorely appreciated. We aren't total idiots mechanically - we did a supercharger service and replaced a whole manner of parts ourselves but we really do not know what to do. I will attach the codes. There is a couple battery related errors but it's because the car has been sitting and those weren't there before.
Here are the Codes :
U0447-00 Invalid data received from gateway A Historic
Dude, you have a stack of codes. P0300-00 & P1315-00 Persistent misfire
Are both triggered by the same method. 0300 sets early, 1315 sets much later after misfires continue for a long time. Both of these are set because of Cylinders 4,5, & 6 misfires.
From your description, I'd expect to find a poor electrical connection in common with ignition coils 4,5 & 6. This commonly occurs when people perform some work in this area. It is most often the ground connection when you have every cylinder within one bank reporting misfires. This type of poor electrical connection can also cause every fuel injector within one bank to perform poorly.
I'd dig into Bank 2's ignition coil grounding wiring first. While you're in there, I'd inspect every electrical connector coolant spilled on.
Any connection less than perfect will not work when high performance is engaged.
I wouldn't buy any injectors, coils, spark plugs, or fuel pumps.
All 3 injectors in only one bank never fail together, while the other 3 in the other bank didn't fail. The same logic holds for coils, and spark plugs.
The replaced coil from elsewhere, will not cause problems elsewhere. The act of replacing that coil with errors made, spilled chemicals, dropped fasteners, electrical connection stresses, often do cause problem dominoes to fall.
P0430-00, likely caused by misfires, ignore until you stop misfires
P065C-01 Accessory drive belt tension incorrect on Generator, or maybe coolant spill caused belt slip. I'd check belt condition, generator bearing, idler pulley tension, generator electrical connections.
Battery voltage after overnight, Charge Voltage, battery connections, every power and ground connection from the battery all the way forward.
Much of this sounds like the Starter Battery is too weak. I know that will not make sense, but we have all fought through electrical craziness, then solved it all with a new battery.
Once you know the battery condition is good, then I'd start working on the CAN Bus troubles.
From the Service Manual for misfires. This is listed as number 1 on the diagnosis list.
"Inspect the wiring harness for the ignition coils and fuel injectors. Ensure that the electrical connector pins are not backed out or corroded and the electrical connectors latch correctly"
In this case I'd check for fluids in the connectors. And since a person was working in the area, be sure none of the pins have pulled partly out their connectors, and that all pin crimps securely make connection to the wire.
It's highly unlikely 3 fuel injectors in Bank 2 all failed while all 3 injectors in Bank 1 didn't fail.
Pressure in the fuel rails is high enough to cut through flesh and bone quicker than a chain saw.
I doubt anyone could remove and install these injectors successfully without the Procedural Documentation or recent experience. There are many opportunities for errors.
Besides all that, you do not have 3 bad fuel injectors in Bank 2.
Injectors are often replaced, but it's rarely useful. During the act of replacement, Dealer Techs, and others, fix all the electrical problems during the process. The problems get fixed, they sell 6x new injectors, everyone's happy. But none of the 6 old injectors were bad.
Without removing injectors, you can measure resistance. I looked around but didn't find the spec. That's easy to solve, just measure resistance on Bank 1's injectors. Bad injectors are typically open, so resistance is infinite.
The injector wiring harness is in common with every injector in bank 2.
The ignition coil wiring harness is in common with every ignition coil in bank 2.
Here's what the Repair manual shows as the most common repair action resulting in repair.
"Inspect the wiring harness for the ignition coils and fuel injectors. Ensure that the electrical connector pins are not backed out or corroded and the electrical connectors latch correctly"
I use a water spray buttle to locate vacuum leaks. With engine at idle, I just squirt a bit of mist at the suspected area.
The V6 firing order is 1:4:2:5:3:6, so by Bank it's, 1,2,1,2,1,2. The V6 actually alternates between Banks, the V8 Doesn't.
The HPFPs alternate pushing fuel to the rails. This is important because only one HPFP is in common with Bank 2. These pumps most common failure is again, the wiring harness.
I'd just disconnect at the pumps, inspect visually. These wires only power a solenoid, the pumps are mechanical, engine driven. The solenoids let fuel into the pumps equal to the fuel needed per combustion event. A gimpy electrical connection or sticky HPFP solenoid can cause lean fuel supply during high power demand.
I doubt it here, because of the work done in the ignition coil area. I only show it because it is a possibility. And certainly, do not pay for a new HPFP when it's more likely a wiring harness problem, it's fine to throw parts at a problem, when money is not precious.
Help with misfire! From cylinder 4 to 4 , 5 ,6
. Already spent upwards of a couple thousand on an entirely new coolant system to fix a leak. 
