Sounds like it is pushing too lean... a vacuum leak was a good first guess and I still wouldn't rule that out until I cap every vacuum line. IAC is a possibility, fuel starvation is a possibility. If I could catch every new 1st generation owner, I would tell them to buy an EVTM manual, an ODB-I reader, and a fuel pressure gauge right up front. The ODB reader isn't going to be much help to you on this though, all those disconnected parts, you are going to have codes like crazy no matter what.
It ran fine, sat for a week, and this started happening. You know, with all that stuff disconnected, it's trying to run on the computer's internal calibration rather than using sensors, it's in a fail safe mode, and that will work... albeit with lower horsepower and lower mileage. But maybe it's not able to go back to the failsafe mode for some reason. I might try disconnecting the battery overnight, just for grins... see if a computer cold reset gets you back in the race. I might borrow a fuel pressure gauge from your parts store, usually that's a freebie.
Yeah, I would unhook the battery overnight as a first step, then plug all the vacuum ports to rule that out because it's such a good match for the symptoms, then fuel pressure test. I would not buy more parts until I did these tests.
