I know its a GM website, but i'm not a car guy so...yeah...
1993 mercury villager v6, all i can say is when i remove the spark plug wires for cylinders 2 and 3 nothing happens, if i remove any other spark plug wire the idle lowers and it starts sputtering/dying. Also the idle is extremely low at stops and the engine chugs when im at a stop in drive... New spark plugs/wires, new fuel regulator valve, cleaned throttle housing and IAC, still dont know the problem though.... is it a misfire? The spark plugs for cylinders 2 and 3 get a spark, soo....idk. don't have a computer dealy to check codes either

Start with the basics and do a compression test. If it has compression check for injector pulse.

I agree, it sounds like you have 2 dead cylinders, and you need to find out what you are missing, whether it be spark, fuel, or compression.

With it being a Nissan platform, I am completely lost. Sorry.