High Idle and White smoke on startup

Hi guys im brand new into b series trucks and brand new to the forum so if you could spare some patience with me it would be much appreciated.

So I drive a 1992 B2600i 4x4 with a 5 speed, and as the title says i have really high idle. Around 3k on cold start as well as some white smoke but only on startup. it also idles high once it gets to operating temp, right around 2k.

If you've got an idea PLEASE send it my way I'd LOVE to hear anything and everything.

Thanks for reading
Evan

Get your computers tested fam, or possibly your spark plugs?

Intake leak or vacuum hose broken/off. A vacuum operated switch could have a broken diaphragm.
White smoke only at start up can be condensate accumulating in the exhaust . During cool down, air (moist) is drawn into the exhaust, but burns (evaporates) off during warm up. Also bad valve seals will allow oil to seep past clearance between valve and guide with old (dried out, cracked) seals. This too will stop when warmed/burned off.

How many miles are on the engine? White smoke usually indicates water, which could be a head gasket that has started to fail. You can open the radiator cap when the engine is cold and see if you can see bubbles in the coolant with the engine idling You may be able to re-torque the head if the bubbling is not too bad yet.

As far as a high idle goes you could have a Idle Air Control valve that is getting sticky or some other sensor starting to fail. You could spray some carb cleaner at the base of the intake manifold and see if your idle quality changes.

Additional help may be found here: http://www.troublecodes.net/