cold start

[ddog888]

i have a 1999 chevy silverado 1500 -5.3. when the weather is cold,usually below 20

degrees when i start the truck it will idle fast then slow for 2-3 mins. then it will idle normal. it did this last year then went away when the weather warmed up .

the check engine light comes on also. what would cause this.also my heater fan switch will not work in the 1-2-3rd position only 4 and five. do you thik it is a bad

switch?

thank you

dennis

[GM-Tech]

First, find out what code is stored as a result of the check eng. light being on. It sounds lean. What's the fuel pressure?

 

As for the blower speeds, it's the blower resistor or module. This is a very common failure. This is mounted right by the blower motor under the right side of the dash. Just find the blower motor and follow the wires from it and that'll lead you to the resistor/module... which is real close by.

[BRZ71]

Sounds like what I and another guy have on here. Mine was fine for a few weeks but today it got down under 40 and it started doing the same thing again. Mine will only do it when it colder than 40 outside.