1991 Plymouth Laser RS Turbo 2.0

I have a 1991 laser it has a a few problems 1) idle speed is every where but nowhere near where it's supposed to be specs say about 750 I don't go any lower than 1000 I idle back and forth between about 1700 and 1000. 2) when I get on the throttle a puff of white smoke comes out my exhaust not sure what is the problem however today I dumped the clutch and a big cloud of black smoke came out the exhaust. 3) when I hit high rpm the engine sounds funny kinda like it's running lean 4) I installed a aftermarket boost gauge and when i'm @ WOT my boost gauge moves from 15psi to 5 psi with the gas pedal steady please help me the engine has had a head job recently (valves t-belt timing belt tensioners lifters the works everything on the top end) new wires, oil filter castrol synthetic 10-40 lucas synthetic stabilizer ngk platnium plugs 50/50 zerex antifreeze air filter