[Vash]

hey all,
another day another question

My sierra when first started in the morning or after work, idles up over 1500-2000rpm for a long time until fully warmed up, can take up to 15-20 mins of driving, then it drops down to about 1000ish

Any ideas? most likely idle mixture?

cheers

[fordem]

What carb do you have on it ? Do oyou have all of the vacuum lines in place?

It's most likely an auto choke problem (assuming that your carb) has an auto choke.

Depending on the carb - there are a number of vacuum lines and a thermostatic VSV that control when the choke comes off, and there may also be a ceramic heater that needs +12V supplied to it after the engine starts.

[Vash]

I'm not sure which carb actually. Pretty sure it's stock standard. 95' 1.3l

[Taylor74]

The water hoses that go to your carby is prob partly blocked making the wax pallet stay on if its the std carby.
They usualy block near the rocker cover in the brass T like fitting as it only has a small hole to restrict the water flow. Try blowing some air through them if no air will pass you can use a small drill bit to clear the blockage down through the upward facing fitting.
Also check that you have a good thermistst the choke wont come off properly until its properly warm and a thermistst that is stuck open will cause the same problem.