Nissan Repair: High Idle, nissan truck, cold engine

Question
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Followup To
Question -
Hi could you tell me on a 1987 nissan truck 4cyl. with throttle body inj. The dealer says the thermostat and a wax kit needs to be replaced to bring the idle down.
Can you tell me what the wax kit does and where it is located and if i can just run the truck without it.
I put a new thermostat in and it still idles high and will not warm up until the outside temp. gets over about 80 degrees i live in Tucson Arizona.
Thankyou in advance.
Tom
Answer -
Tom,

I assume that they want to replace the throttle body as an assembly as I have not heard of a wax kit.  This includes a temperature sensor and the throttle body needs to be cleaned.  Other than that, I think this is the process.
They actully have a part at the dealer called a wax kit it looks like a spring inside of a metal frame but the parts people did not know how or why it is on the motor.
Thankyou for your response

Answer
Tom,

I would not think that a wax kit would keep the idle down.  But, if this is like the thermostat that keeps allows the idle to drop it would work for that purpose. Now, for the cold engine part...  If the thermostat has been changed and the temperature is still cold I would be looking at burping the heater core by loosening one of the lines at the firewall and letting the air out.  The engine has trapped air and that is what is causing the problem.