So my car is idling pretty high, 1300-1500. So i disconnected the Idle sensor and set the idle again. and it was working fine. I connect the sensor back in and bam it goes back to high idling. Whats wrong? Time for a new sensor? its not even that old. Or tuning will fix this?
By sensor, we will assume you mean the IAC (it's not really a sensor and I wouldnt have brought it up but I just wanna' make sure we're on the same page).
It might take the puter some time to relearn what DC the IAC needs (it doesnt know you did anything so it keeps the DC where it was until it sees how far above the commanded idle it is, and lowers the DC).
You will want to pull codes (look for a code about not being able to control the idle). Also, if you can datalog IAC function (duty cycle), I'd see what it's doing.