I come back to the well after many hours in faq and still more hours over many days fiddling under the hood. I've learned tons in the faq and from previous answers and as a result, have taken care of things that sorely needed doing. Thank you all for that.

But the car is still surging at idle, and so now here I am.

Main question: When the AMM disconnect-limp home test stops the surge, as it did, does that necessarily mean the AMM is bad? Or could it still be vacuum leaks etc etc etc. The car idles roughly with the AMM unplugged, as you would expect, but does not surge.

The surge (nicely described as loping by someone else) starts after maybe 30 seconds of operation, and is constant at idle. Sometimes when trans is engaged, that holds it steady at a stop. Other times, I have to put it in neutral so as not to stall.

Otherwise it drives/accelerates fine. But gas mileage seems poorer. And when this started, I would smell gas. I don't smell that so much anymore, although that could be a result of fried brain cells.

Here's what I've done:
-Removed and thoroughly cleaned idle air control
-Cleared the thoroughly clogged flame trap, replaced the small hose from it (clogged), cleaned the larger hose from it, ensured the fittings were clear.
-Cleaned the AMM with AMM spray, twice. The first time, this immediately fixed an earlier stalling/missing problem, and gave me a few weeks of peace before this started.
-Cleaned the accordion intake hose and plugged a small crack in it with jbweld. (new one is on order)
-Cleaned the throttle body, ensured butterfly valve was operating, got lots of gunk out, but did not remove it.
-Pulled the vacuum hose off the fuel pressure regulator to check for gas, didn't see/smell it. (I didn't start engine, should I?) I did not try the trick where you attach a long hose to the other side and see if the gas shoots into a container.
-Replaced air filter and disconnected the pipe feeding hot air to the box thermo.
-Can't find any leaks, though the hose holding the flame trap is split at the end. I've ordered a new hose, flame trap, aftermarket intake hose.

If the answer to the Main Question is, yes, the AMM is definitely bad, then I'll bite the bullet and go for it.

And I have a crack in rear muffler, have assumed that would not be part of this.

Thanks for your patience and support!