Change spark plugs now smoke

Does the squeal change when you rev the engine? That would usually suggest the alternator drive belt is loose or old.
Are you sure the smoke is white? The colour gives a good clue to the problem.
If oil was getting into the engine the exhaust smoke would have a blue tint to it. White smoke suggests coolant is getting into the cylinders. With the engine Off check the coolant reservoir for oil on the surface layer. Also check the oil filler hole. Is there a "mayonnaise" like substance there. These signs suggest there is a problem with the head gasket.

I would`nt be too worried about the oil on spark plug threads be more concerned about white smoke! it sounds like head gasket problems.Good-luck.......

Changing the plugs probably had nothing to do with it.
White smoke is usually a sign the engine is burning coolant or trans fluid. You might want to check those fluid levels.
If the coolant is low, you may have a leaking head gasket or intake gasket.

Sounds like either a blown motor (rings need replaced) or a bad head gasket or cracked head.
If the rings are bad your car would have felt like it was losing power because the engine will no longer have the same high compression that it's required to turn the wheels. You may have heard your engine knocking or seen a light blue colored smoke coming from your exhaust as a result of your engine burning up oil in the combustion chamber from the rings leaking.
If your head gasket is leaking or your head is cracked you'd likely find milky looking oil when you drain your oil from water/antifreeze being mixed in and noticed a white smoke coming from your exhaust that is actually water vapor coming through the exhaust.
If your car was running rough when you last shut it off try pulling all of your spark plugs and either cleaning them or replacing them all. A bad head gasket or bad rings can both foul spark plugs. A car will run rough with 1 or 2 fouled plugs, but once enough foul it will no longer run at all just sit and crank over. If changing the plugs get's it started for ya, check your tailpipe first for water, if nothing, change your oil. If no signs of water/antifreeze or milky colored oil then it's probably rings.

should be idling roughly
engine check light on ?

faulty coil ok when cold no good when hot

do a compression test on number four
no compression on cylinder four

leaking intake or exhaust valves
the injector isnt working
if everything looks ok and no better
a blown head gasket

ok do a spark plug change also have the spark plugs check to see if you have loose spark plug.sometimes the white smoke means you have to much oil in the motor and or your piston rings are going out.use a bottle of see foe in the gas tank and in the motor but make sure you get the oil change ok .that should fix the problem

seems like you are leaking antifreeze inside your engine have it checked white smoke usually means antifreeze

Replace the head gasket.

black smoke is fuel white smoke is oil. change your spark plugs to a hotter plug and run with some hpr 50 engine oil or somrthing nice and thick

You changed 6 coils, but you didn't change spark plugs? The new coils give strong spark to burn off resisdues from your old plugs plus what ever left inside the combustion due to bad old coils causing smoke and bad ordor. Change all new spark plugs so you can have good ignition to burn off all junks inside combustion chambers. Smokes are at the beginning, but it will go away after less than 10 minutes.
If it is not going away you may have other problemS:
Rich mixture causing engine check light come on.
Check if engine oil level.
Check if your coolant level.
Open the oil cap to see if you have milky stuff. If there is milky stuff then you have bad head gasket.
Let me know what is coming out so others can learn from your experience. Good luck.