Prelude doing crap .... help

start up engine leave it warm up , engine sound fine but
if i press the gas (just one and leave it running) the engine idle going up and down , engine sound crap . if i press the gas couple time and hold at 4ooo rpm for 40 second the idle back to normal ...
One thing i know is like water coming out my exhaust every morning. the place i park now all black ... anybody have this problem before please help .... i think is cooling problem. Radiator i drain , refill and leave run 10 min i did like 5 time but no help different day .. now give up
help needed thanks

Did you bleed you fluid? Because sometime air in the engine will do that because i think you iacv reads the temp of you radiator fluid and if there is an air bubble the sensor doesn't understand. The iacv might be bad too.