1999 Pontiac firebird 3.8

Okay so I bought this firebird, and It had been
sitting for about nine months. I bought it drove it to
my house about 30 miles from location of
purchase. And I changed the oil and sparkplug
brakes and rotors and calipers all the way around
well I took it out on the street to see what it could
do and it has no torque like to inch up into a
parking space I have to almost floor it and once it
gets up to about seventy and I slow down I swe a
puff of smoke coming from under the hood but
when it's idling it doesn't smoke and the gauges
don't go haywire it doesn't get hot I need help it is a
projet car for my dad so please help