Rough Hot Idle - 1992 2TZ-FE - The Saga of Njordi

Have you checked fuel pressure? When mine had a bad fuel pump, it would often idle rough when warm, and sometimes would take lots of cranking to start, or simply not start at all.

Good thought, I have not checked fuel pressure. I am hoping the weather next weekend is good and I can do some wrenching.

Scorched earth mission to renovate Njordi continues. I just order all new OEM injectors and seals, found an OEM fuel pressure vsv, and a Delphi brand fuel pressure regulator. An expensive bill for sure, but it feels like all these things are good to refresh even if they are not the primary problem.

Have you verified spark yet? When you turn the key to "Run" position, do you see the little engine icon/light on your instrument cluster?

I do not have the special fuel pressure checking tool, but the pump runs and the squeeze test on the fuel lines seems like the fuel pump is working. Also found that the injectors are actually discontinued, so I guess I will visually inspect them when I pull them out and can replaced with reman injectors from RockAuto if needed.

I have not checked spark yet, but I can once I get the passenger seat out. The only piece of the spark circuit that isn't new OEM is the coil. Maybe I should just swap that out anyway...

Verifying the CEL light on your dash is the 1st and easiest thing to check. Does it illuminate when the key is in the run position? Codes should be next, then spark and fuel pressure. When activated, if the fuel pump runs, you will be able to hear it flowing through the system.

Yes, I am still getting the CEL and the full compliment of codes 22/24/32/41 which is all the signals that run through the connected circuit of the MAF/water temp/TPS/Air temp. I am not saying these are definitely not the problem, but I am saying that all those sensors/devices pass the tests shown in the factory manual. They are all within spec and I can find no shorts or weak connectivity in the wiring.

Also just confirmed that I can indeed here fuel returning the to the tank when running the fuel pump by jumping FP and +B in the Diagnostic port. So I think I can at least skip the fuel pump for now, which is nice because they are pricey.