Finally got this one figured out.
Turns out the problem was, really, no problem at all.
Tom (1turbofocus) and I had a trouble shooting session. Here's how it went down:
- Checked intake boots, crank position sensor, and re-checked for spark. All came back good, but the spark seemed "weak".
- We set up an SCT datalog and had the key in the ON position for the remainder of the troubleshoot. Tom wanted to first get the car running. We used a gas-soaked rag on the intake, before the MAF, and WOT to try to get it to run. It allllmost caught. A few more tries failed.
- Here's the fun one. I removed the fuel pump fuse, and started it with WOT again. It was able to run, but still couldn't hold an idle.
- With the throttle at WOT, replaced the fuel pump fuse. It started up again, same condition. How or why the car started without the fuse in I have no idea, and frankly I don't care anymore lol.
- The car ran like absolute garbage at this point. Lots of backfires through the intake, seemed to not be running on all cylinders, and tons of smoke from unburnt gas out the exhaust. I could kind of keep it running with the throttle, but it would barely respond to throttle input. WOT would barely raise the RPMs. At this point, I personally would have shut it down for fear of damaging the engine through timing issues or otherwise. Tom urged me to push on.
- Eventually, the car started to get closer and closer to operating temp. As it got there the idle and running condition improved bit by bit. Things were looking ok...
- By the time it got to 180 degrees, which took forever with the cold temps here, it was running as normal as it could be.
- A short test drive confirmed that the car is back to normal.
Our theory was that the spark plugs were so fouled out by all the starting attempts that they just needed to get hot to un-foul themselves and allow the car to run. To get an idea of how much gas was sent through in the past week, I started this with a full tank, and put 2.2 miles on before the issue started. I'm now at 7/8ths of a tank lol. Those plugs didn't stand a chance. I'll be replacing the plugs.
TL;DR: It was the fuel filter and fuel pump. By trying to get the car to start again, the plugs fouled out. Once the car could be started and reached operating temp, the plugs were happier and the car ran great.