well i put a d16a1 integ motor in my 89 si , all sensors are plugged in and i have the right ecu for that motor but my idle is no lower than 2K and after drivin the car for a lil the idle keeps going up and down by itself.. i replaced all sensors and it still does it. it stops if i unplug the TPS sensor but then it drives bad and the idle goes even higher// there are no vacuum leaks and the coolant was bled three times so what could this be? it happened when i had my single cam too when i put a diff mani on it but then it stopped. any ideas?

 

mine does the exact same thing, im stumped

 

check your throttle body gasket.