Warmup problem?

[REn0]

Hey guys i've searched but did'nt find an answer so. I'm just wondering about my car when it is warming up it sits at about 2000RPM, and in a few minutes starts waving up and down from 2000 - 1000, making a whirring noise while doing it, like some one is revving it, then after about five minutes of it going up and down it heats up and sits normally, is this normal?

[shepherd79]

no it is not.
Your fast idle should be around 1500-1600 rpm.
The reason the fast idle jumps like that is because of the fast idle valve. It is coolant controled and has a spring inside. When spring sags, the rpm start to jump.
Solution:
You have two choices. 1. got to a dealership advance autoparts and get a new one. it can be very expensive. 2. adjust it. it would take 5-10 min max and it would fix the problem.

if you decided to go with #2, it is easy to do. the fast idle valve is located on the back of the throttle body. It has a cover with two screws holding it. unscrew the cover and remove it. with a WIDE flat screw driver turn it clock wise while the engine is running. Turn it untill the rpm stop jumping and lower down to 1500-1600 rpm.
In a few situations, you may gave to adjust the idle after the car warms up.