Thanks for the suggestions.

I'll have to check out the in-tank pump. I think it's probably fine because I don't have any issues with power and the car pulls steadily to redline. But it's worth checking for sure.

I may pull the injectors again and send them out to be cleaned. The techron can only do so much. At some point the injectors need to be professionally cleaned/restored.

I've also read the coolant temp sensor (not the one for the gauge, but the one for the ECU) can cause idle issues.

My ICV could be "lazy" which would account for the lumpy idle. Though the RPMs stay steady.

I'll see if I can find another AMM to play with. I'd also like to see if any '93 240s with the LH 2.4 only have 5 pins in the 6-pin AMM connector (AMM has 6 pins while the car's AMM connector harness only has 5 female slots and 1 empty slot). Though I think I'd be seeing a check engine light if my AMM connector harness was damaged, right?

The idle is hard to explain. The engine shake isn't violent, but I think it's shaking more than it should. Almost like an intermittent misfire. I've unplugged each injector, one at a time, and the engine shakes much more violently when I do this.

- Mike