So I'm having idle issues again. No idea whats causing this what so ever. Before the car would idle really low and then I fixed it and it was right where it was supposed to be , but now when I let the car warm up from cold its up around 1k rpm and gradually comes down to around 800 to 600 rpm and maintains that. Now it goes up to about 1k rpm, slowly drops down to 800/600rpm, and then drops down to like one bar above the 0 mark. What could cause this? It doesn't sputter or stall or hesitate or anything at all.

 

A TPS that needs calibrating, a dirty/faulty MAF, a dirty IACV, then the usual, spark plugs/wires, dirty fuel injectos ect

 

you change the battery or reset the ecu lately? usually when it starts to change how it idles.
either a small issue like sc400slide said or your ecu needs to relearn again after another reset.

 

I have the same issue except on a 1J. Guess I'll try calibrating the TPS.

 

I'll run some injector cleaner in my next tank up. Its possible the IACV is dirty I mean its stock from 1992