97 gst problem please help!!!!

[gst97psi12]

so i have a 2g 97 gst 5sp and its pretty much all stock.. when i cold start it.. the rmps jump around from 400 to 1000 and it sounds like it has a miss.. my cheak light is on and says muilte cilyinder missfire so i changed plugs and wires.. please note when it is runing down the road it is perfect and holds boost and vary fast just at idle it runs like shit and sounds like a miss.. any ideas on what i should do? thanks

 

[zachhoward]

what you got for a air filter i had a similar problem and my air filter was pluged

 

[gst97psi12]

just a cheep o cold air one from autozone but its brand new

 

[zachhoward]

did you start having this problem after putting it on

 

[gst97psi12]

um im not sure ### i bought the car with it allready on... it runs fine just at idle its like it has a miss and its vary rough.. after it warms up it goes to the right rpm about 750 to 900 and it wont jump around but it sounds like shit and spits and i dont like it...