So where does this leave me? By process of elimination what else can there be?
Ooof. You are running low on items to check/replace. Live data from SDS / HHT-Win would be helpful at this point, to try and spot anything out of the ordinary.
- Mass airflow sensor? I'm not getting a code or anything
As a test, disconnect the MAF and see if there's any difference. If it runs better (or normally) with the MAF disconnected, this would be highly suspect. Live data would prove the MAF good or bad.
- Stuck cam magnet adjusters? Does this ever happen?
Never heard of this happening, but if the magnet is not operating, midrange power is really poor. If stuck advanced (which I've never heard of), the idle is really rough. You can test by manually applying +12v to each cam magnet, the idle will get rough when either one is energized at idle. (HHT-Win has an activation test for this.)
- Some vacuum leak somewhere in the intake I can't find, possibly at the injectors or intake manifold seals?- I don't own a smoke machine but I wish i had one
Since you are running low on options, a smoke test is something that would be worth trying. You can build your own smoke machine, or buy a cheap home-made one on eBay. Compressed air is required.
- Need to check that both magnets are installed on the flywheel- car had a transmission installed recently by previous owner. Could flywheel be misaligned?
The flywheel can only be installed one way, 1 mounting bolt is offset so it will be forced to the correct position. If one magnet is missing, you'd likely have a recurring fault code 18 on the EZL, along with intermittent hard starting. I had 1 magnet missing on a car years ago, took me forever to figure out what was wrong.
- some kind of clogged or failure of an emission component? Clogged cat?
Severely clogged cats will cause power loss under load. Can you drive the car with the vac hose disconnected from the EZL? Alternately, disconnect the exhaust crossover pipe to bypass the cats and see if there's any change.
- What is this MOT thing near the EZL?
That's the carbon canister purge valve. The MOT valve will cycle to ingest fuel vapors from the canister. You can disconnect / block the hoses at the valve for test purposes. If the valve is stuck open, it would cause a pretty significant intake vacuum leak. Also check the 8mm black pipe from the intake manifold (connects to PVC hoses near cylinders 5/6) to the valve and make sure it's not broken anywhere.
Live data would help here, but the O2 sensor is only in the loop after warmup. I doubt this is related, but a new sensor wouldn't hurt.
- Did the timing chain jump? Would it even still run if it jumped a tooth?
Also unlikely, but worth checking. The engine can run amazingly well with one cam 1 tooth off. I'd be really surprised if this was the issue, but with any M119 purchase, you have to pull the valve covers anyway to check for broken chain rails, and while it's open you can check cam timing.
- some issue with a knock sensor or other sensor somewhere on the block
Also unlikely... knock sensor shouldn't cause this. Guess you could try disconnecting it (3-pin connector at EZL) and see if there's any change?
There really can't be that much else right?
I'm pretty sure a this point I'm going to have to buy an SDS. How detailed of information will this SDS system give me? Will it tell me if I have a vacuum leak?
SDS provides a lot of data, but you need to know what you are looking at. The video below shows most of what's available. It won't tell you specifically if there is a vacuum leak though.
Is it sophisticated enough to give me a clear idea of what the fuck is going on?
Maybe, maybe not... depends what the root cause is. For example it can't tell you if there's a fuel pressure problem, or clogged cats.
