1997 4runner 3.4 liter is loosing coolant to a cylinder. slight miss and sweet white smoke from the exhaust. runs cool and not perkolating at the radiator. will smooth out after a few mins

White smoke normally indicates an internal coolant leak from a bad head gasket or a cracked cylinder head. A healthy engine will have some steam/vapour from the exhaust when starting from cold but dissipates quickly. If your exhaust smells 'sweet' it will more than likely be coolant making it's way into the combustion chambers. Check your spark plugs. Coolant entering a combustion chamber clears carbon deposits so if one or more of the plugs look suspiciously clean, it will indicate the probable location.

he causes of white exhaust smoke can vary; however, it is common to see white exhaust smoke when first starting a car, especially on cooler days. This is generally steam caused by condensation. As the engine warms up and the condensation dissipates the white exhaust smoke (steam) is no longer seen. If excessive white exhaust smoke is present well after the engine warms up, it is necessary to have the car inspected for possible internal coolant leaks. Indicators of an internal coolant leak include billowing white exhaust smoke accompanied by a sweet odor or a low coolant reservoir level. An internal coolant leak can also contaminate the engine oil giving it a frothy, milky appearance. Even small amounts of coolant entering the combustion chamber will produce white exhaust smoke.
One of the main causes of white exhaust smoke and coolant loss is a cracked or warped cylinder head, a cracked engine block, or head gasket failure caused by overheating. A cracked head may allow coolant to leak into one or more cylinders or into the combustion chamber of the engine. Dirty coolant, a poorly maintained cooling system, a low coolant level, or a non-functioning cooling fan can cause engine overheating. In addition, engine wear can eventually cause the gaskets to lose their capacity to seal properly allowing internal coolant loss. Intake manifold gasket and head gasket failures are two of the most common sources of internal coolant loss caused by engine wear.
Never remove the radiator cap or coolant reservoir cap while the engine is hot or running as it can cause serious injury; always allow the car to cool down completely first. Checking for a low coolant level in the reservoir is the first step in determining if coolant loss is causing the white exhaust smoke. If the coolant reservoir is at the proper level but excessive white exhaust smoke is present, a cooling system pressure check is required to determine where, if any, coolant leaks are located.

White smoke usually is coolant burning. Is engine loosing coolant? Small pop could have been head cracking, or possibly head gasket failing. If you are loosing coolant, time to remove the head to see what failed.

It is common to see white exhaust smoke when first starting a car, especially on cooler days. This is generally steam caused by condensation. As the engine warms up and the condensation dissipates the white exhaust smoke (steam) is no longer seen. If excessive white exhaust smoke is present well after the engine warms up, it is necessary to have the car inspected for possible internal coolant leaks. Indicators of an internal coolant leak include billowing white exhaust smoke accompanied by a sweet odor or a low coolant reservoir level. An internal coolant leak can also contaminate the engine oil giving it a frothy, milky appearance. Even small amounts of coolant entering the combustion chamber will produce white exhaust smoke. One of the main causes of white exhaust smoke and coolant loss is a cracked or warped cylinder head, a cracked engine block, or head gasket failure caused by overheating. A cracked head may allow coolant to leak into one or more cylinders or into the combustion chamber of the engine. Dirty coolant, a poorly maintained cooling system, a low coolant level, or a non-functioning cooling fan can cause engine overheating. In addition, engine wear can eventually cause the gaskets to lose their capacity to seal properly allowing internal coolant loss. Intake manifold gasket and head gasket failures are two of the most common sources of internal coolant loss caused by engine wear.
Never remove the radiator cap or coolant reservoir cap while the engine is hot or running as it can cause serious injury; always allow the car to cool down completely first. Checking for a low coolant level in the reservoir is the first step in determining if coolant loss is causing the white exhaust smoke. If the coolant reservoir is at the proper level but excessive white exhaust smoke is present, a cooling system pressure check is required to determine where, if any, coolant leaks are located. THESE LEAKS WILL CAUSE SEVERE ENGINE DAMAGE! Have the car inspected immediately.

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Internal coolant leaks can and will cause

Sounds like you have a blown head gasket and coolant is getting into one of the cylinders.

White exhaust smoke from a gasoline engine usually means coolant leaking into the engine block.
Is the coolant in the radiator full ?

White smoke is a sign of coolant being burned in the exhaust.

Is the antifreeze leaking on the ground? The white exhaust usually signals a bad head gasket which allows antifreeze to leak into the cylinder and burn. I recommend getting it to a garage, its a fairly big job.

Well if you have white smoke when reving up engine then its not smoke its STEAM as you have been lossing coolant by the sound of it (yes) or no,,,,IF yes then you have done a head gasket or something else which
is letting in coolant to the cylinders and when it fires it blowes it out the hot exhaust and causes steam ,, as the only other way to get white smoke could be burning brake fluid/ or kerro.
So does your engine get hot /loosing coolant/missing when running ///any of these will cause your problem.
Let me know how you get on ,, Ron

your cooling system is preasureising due to a leaking cylinder head gasket the white smoke you see is coolant passing through the exhaust valve on the offending cylinder have the cooling system tested for CO content hope this advice helps