i have a code p0505 (idle control system malfunction) in my 99 si. when the mil comes on the idle goes to 2 grand and if i clear the code the idle drops back down to normal. but it comes back a day later does anyone know what might cause this.

 

up

 

still looking for any suggestions

 

Try this:

remove the air duct from the throttle body.

Start your car and block with your fingers the lower port in the throttle body

If the engine stalls, then you need to check the IAC for proper tuning. If it is within spec, you will then need to replace it.

If not, check for vacuum leaks.

 

thanks ill try that in the morning