Ok. The idle speed is controlled by a few different inputs. A temperature related one is the coolant temperature sensor (CTS). IT gives the pcm info and an adjustment is made at the throttle by the IAC idle air control motor.
Get it to operating temperature, shut it off, key off. Pull the harness of of the CTS and measure the resistance.
At 200 degrees the sensor should be between 700-1000 ohms. IF not replace it. IF it is good, remove the IAC and clean it with intake cleaner. The pintle may be sticking.
The car needs to be accessible from the bottom to diagnose the noise. A stethescope can be used to narrow it down. Again, it may be a cracked flywheel.
Thursday, July 24th, 2008 AT 7:43 AM