Decided I'd hit the store, since she was in a good mood, and get tuna to mix with last night's leftover macaroni and cheese. (Incidentally, Kraft's "delux" M&C is not very good.)
Bought a few needed things, got home, unloaded the groceries, and then remembered that I still didn't have any frigging tuna.
Had a gander at the Jeep's engine bay. Nothing looks wrong, the new ground is tight. Identified the TPS, IAC, MAP sensor, but could not find the fuel pressure regulator.
Then again, the fuel rail hasn't got an outlet. Most fuel injection systems loop back to the fuel tank; the fuel pressure regulator is on the fuel rail and diverts unneeded fuel back to the tank. This works well, particuarly in cases where the vehicle is run out of fuel, because it pushes the air right out and lets the system repressurize nice and fast.
The Jeep, however, has no obvious return line, meaning that the pressure regulator is probably at the tank, or near to it.
Og suggested this may be a fuel pressure issue. He may be right; the fuel pump is the original, and guess where the fuel filter is? On the pump, in the tank, of course, else I would have changed it.
But the problem I'm having is intermittent and that doesn't make a ton of sense to me. Further, it appears to go away after I've run the engine for a little while with my foot on the gas. That could be fuel pressure issue, or it could be something else. I believe I've eliminated grounding as the source of my woes.
Biggest fear is that it's a vacuum leak, as has previously been suggested, because finding one of those is a friggin' nightmare. But it baffles me how a vacuum leak could cause an intermittent no-idle condition.
Second biggest fear is that the ECU is getting flaky. That's a spendy part, even for an 18-year-old truck (or maybe "especially"). Well, kinda spendy; about $200 or $250, which is what I paid for the AC compressor--but that was an emergency, having only just started a new job two days earlier.
But compare $250 or even $300 to the cost of getting a new car. Discuss.
...so I don't really know what I want to do yet; I only know that I need to do something because even a work-at-home guy needs transportation. The thing runs fine most of the time, so it's just a matter of finding out what makes it not run sometimes which--as I said--will likely be an exercise in frustration.
And of course it's winter.
But as I said, "work from home" means it's a hell of a lot less pressing, so I should be able to take the time I need to in order to get the thing back to 100% reliable.