white smoke at start up..

when my 95 riviera sc is cold white smoke comes from tail pipe for aboutv5-6 secs then goes away,what is causing this white smoke on cold start up,it doesnt do it once car is warm please help..

If it's a light blue grey smoke, it's probably a small amount of oil being burned when you start up. If you have high miles on the engine, this is a sign of wear, but doesn't effect the overall operation. As long as it isn't happening when warmed up, I wouldn't worry about it. You may notice a small decrease in oil level between changes. Only way to fix is to rebuild the engine.

If it's really white, all engines emit some steam for a few minutes when it's humid or cold out. Perfectly normal.

Have someone start your car while you smell the first exhaust fumes. (note- keep it under an hour or till faint)
If it smells sweet you probably have a leaking intake manifold gasket, a very common issue.
not big trouble unless cylinder fills with coolant.
I would check all spark plugs for signs of fouling, one or two more than others.
other symptoms are, loss of cabin heat,
frequent replenishing small amounts of coolant ,
slightly higher temps or over heating,
or the inability to purge air from cooling system.
gaskets aren't tough repairs just time consuming .
the amount and time of smoking indicates severity of any leaking.
if any leaking is indicated it should be addressed ASAP.