I have a 87 gta 350 that has been sitting for two years. I have replaced the plugs, wires, air filter, and old gas. it will idle ok but when i put it into drive and press on the accelerator the engine bogs down and surges. if i apply the accelerator very very slowly it will slowly go pick up speed. once i have it going about 50 mph the problem is not as bad but if i press it to the floor it will bog again.
i havent checked the vacuum lines yet and i dont know where to go after that.

 

You didn't say you replaced the fuel filter. Try that. It could be plugged. When you increase the throttle you put a demand on fuel and it can't force enough through the filter to feed the motor

 

I have a 88 which sat for 3 years. The fuel rail and regulator were pluged with white fuel deposits.
I cleaned everything and the car still ran slugish and poped and backfired. also the O2 sensor read dead lean. I instaled a set of LS1 injectors and the car runs awesome and went right thru E check.

 

i just replaced the fuel filter today and the problem still persists. ill try the injectors next, thanks for the advice guys.

 

Try replacing your coolant temperature sensor. Your symptoms are very similar to my 1989 GTA. It would backfire and bogs down. Its ony $12 at Autozone and worth looking into.