A common problem with J30's pushing 200k miles is the MAF sensor. I can't remember exactly what the correct specs were to test it, but the way I knew mine was going bad was that the same symptoms you are describing persisted with the MAF sensor both connected and disconnected. With 180k miles on the clock, checking your fuel pump screen and installing a new fuel filter might not be a bad idea as well. Hope this helps!
Edit: With the fuel tank being in the trunk, there is no need to 'drop' the gas tank. Rather, when working on the fuel pump, you can access it by removing the back panel in your trunk and with (I believe) a 10mm socket, a crescent wrench, and a little finagling you should be able to get the fuel pump out in under 10 minutes. Supra's post has some pictures and instructions that might prove helpful in accessing the fuel tank:
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