91 camaro idle problems

i need some help with my 91 camaro, i have recently replaced the intake manifold and i have nothing but problems from there with the hp {nothing} and in low rpms it want to die... sometime it will jump from 250 rpm too 1000 but if i gas it over 2000 rpm it is fine but with the speed limits i cant do that lol if anyone has idea's please let me know... i have replace my sencors,tps,intake presure sencor,mass flow sencor, o2 sencor,tune up.... i would have to think the intake is bad....

I know you said a tune up.. but have you actually had the car tuned... by a good tuner???

Sometimes changing things like the intake will cause it to need to be retuned.. plus they can tell you if there is something going on in the car that needs to be fixed..

I would think a vacuum leak from either a bad gasket job or inproper torque spec. or sequence.