Stalling automatic

[FuzzayD]

I had the head gaskets replaced and re sealed a valve grind and the exhaust gaskets replaced as well as having the heads machined on my series 1 buick 3800i and since the car has come back whenever i rev the engine above 3.5k revs when the needle drops back down the car will either cut out or some strange grinding whiring sort of noise will come from near where the throttle body is. the car will cut out alot when its cold but not so much once its been going for a while and will 'stall' if i rev it in park, neutral, or any driving gears above 4k revs.
How would i identify the problem? Ive been reading the posts on here and its seems to be close to an air leak or cas or dfimodule or even the fuel pumps or coils.
Can anyone help me identify the exact problem? i dont have enough cash to fix all the possible issues and then find out nothing has changed.

[jas98]

could be fuel pressure regulator or the IAC valve

[FuzzayD]

the fuel pressure thing still works i can hear it turn on. how would i tell if tis the iac?

[iRiot]

i have been have problems with stalling too for no reson i have fuel and power when i give it then slow for a corner and turn it stalls sometimes i was thinkin its when its low on fuel the fuel moves from the pump and loses pressure?

[FuzzayD]

I got tired of not knowing why this problem happend and took my car to a mechanic
he looked round and said that 2 plugs werent pluged in and a vaccume hose wasnt attached ^^' then he said dont worry about cash mate i cant do the math for 2 minutes of work.