Choke problems Normal idle speed even when cold starting. Does not high idle.

SOURCE: engine stalls after cold start-up & release from high speed idle

I had a similar problem.  I found the filter cartridge below the pcv valve had carboned up, and after the crank case pressurized, oil was forced out the pcv supply line to the throttle body.  The idle air control valve solenoid got oil in it and caused my problem, but only when it was cold.  The pcv cartridge is accessed by removing the pcv valve and the rubber fitting that the pcv valve mounts in.  It can then be fished out with a pick set, and it is a pain because you can't see it, but you can get you hand back there.  I hope this helps you.

SOURCE: have 1987 nissan sentra wagon 1.6 carb.engine the

Check your Ignition timing before anything
check your plugs see what color they are
red or orange means carb is to lean , black
or oil means to rich then you can go from there
and set mixture screws on carb , let me no how you make out .

SOURCE: High idle speed when the engine is cold

The high idle speed at start up is normal. As the engine temperature increases, the engine idle should kick down automatically. Insofar as the emissions results, if there were a problem, the check engine light should be on. If it is, take the car to an autoparts store and have the fault codes read. Most parts stores will perform the scan for free. If the check engine light is not on, and the idle question was all you were worried about, you are good to go! Hope this helped and best wishes.

SOURCE: 1986 Honda Accord DX - too high idle on cold start

1986-1989 Honda Accord with Carburetor have a very bad habit that is little known even by most mechanics but easily fixed at home. The vacuum port on the choke opener that is connected to the intake manifold and both vacuum ports on the fast idle unloader get plugged up with nasty hard carbon almost as hard as metal. When this happens the choke sticks closed and the idle sticks on fast idle when the engine is cold and nobody can figure out why. All you have to do is attach a small drill bit to the end of a flexible socket-driver extension and put it in a variable speed drill that will let you run it real slow and carefully drill out the vacuum ports that are plugged. After they are nice and clean use a vacuum pump tester to make sure the choke opener and fast idle unloader are working before putting it all back together. It's amazing how much better the car runs after cleaning out those ports.

SOURCE: 91 mazda 626 erractic idle surge when engine is cold

My '91 626 did the same thing. I tested the throttle position sensor, and it was good so that wasn't it. The other likely culprit is the Idle Speed Control valve, or Idle Air Control valve, which is a $500 part new (more than I paid for the whole car). I pulled one off a 626 at the salvage yard and got it for 3 bucks, put it on (it's an easy DIY, just 4 philips screws holding it to the intake manifold), however I can't be sure that solved the problem, since I haven't run the car much since then. It would seem the most likely cause, tho, and a cheap fix if you go used. Other possibilities: O2 sensor or Mass Air Flow sensor?