Help needed. Major issues!

[andrew394]

So I brought my dream car coming along a year ago now. Drove it 32 miles before complete failure. Manifold flaps broke the car missing on all cylinders.
all lights on the dash except suspension lights. ( not even sure they work!? never seen them) Anyway long story short I now got some time to work on it. So I brought VCDS system and software to look into the car, I brought a brand new battery for the car as the old one must have been bad as held no charge. So a new battery started scanning the car. All went well over 250 falt codes. So I cleared them all via OBDII ( from what I understand quick clear ) to have 114 codes left.
But all of the codes except 2 are all due to low or no voltage. This is from all parts of the car from boot lid lights to headlight wipers and everything in the middle.
So I started pulling panels to find fuse boxes and relays. No fuse is gone or relay. So I turn the car on it does run just badly. To test the volts from the battery before start and during. 12.08V while the engine is off. up to 14.9 volts with everything in the car on and running and at 1,200 rpm.
So from what I understand alternator is working as it should.
I started looking into the engine bay as both ECM modules are not responding or no volts.
From my understanding, I'm looking for a major earth point of some sort.

I have checked all the ones I can see, the two in the boot by the battery the two under the right air filter housing.
I do need to replace the manifold so I am happy to start pulling off parts, Almost all connections/airlines on the top of the manifold are broken and missing screw's. So a muppet has done some work on it and has been careless. I have got new harness covers on the way ( the red wiring cover for the coils)
I am asking is there any other things I can start looking for other than hoping I stumble on the issue.

I should add the car is 100% aired out there is no air left in any strut. I get no noise at all from any corner and can't seem to get the car to be a normal ride height. Otherwise, I would have the car sent to a garage for assistance.

As I said any help would be perfect. I am by no means a mechanic but I do learn the car's I own and would like to do the work myself I do understand this is a huge task.

[andrew394]

Okay, so I made a mistake and took a day off the car, Went back to basic's.
Turns out quick clear on OBDII does not clear the codes on this car, or at least not the big ones. So I spent an hour with the car running going into each module and clearing codes.
Some codes come back right away, most did not. And now I got suspension again!! all 4 corners are lifted front right is slightly lower than the rest. So either sensor calibration or a leak. But better than nothing!
I still got my handbrake on and it won't come off, the module is not responding to anything, Before the car was sat it was working perfectly fine. So Maybe just a loose connection?!
Almost all codes now are either no response or point back to the ABS or manifold flaps. I have tried to get the ABS clear but again no response from the module.
Is there any other way to get access to this without replacing the part in question?
After clearing engine codes it's running smoother but not right still. I now have an engine light on that sometimes flashes ( when it miss fires ) I am putting this down to the carbon as I can see it on the right-hand throttle body oozing out the left side is new and been replaced. So I will clean it when I replace the manifold and leak test it. Or replace if needed.

My final bit of a hurdle is as some modules still won't respond could this still be an electrical issue? The car was well cared for before the place I brought it from. So there are 2 years where the car was tampered with and poorly maintained/worked on.
Again any tips or things to look out for please just send them my way. As I said before I am not a mechanic so it might seem clear to you but something I might over look.