Ok, upon shutting down the engine I have loud WHOOSH sound coming from the intake...is this normal?? It has done this since I got it running back in September....and I do have a slight miss at idle too.

Driving it is ok...no surging, stalling etc....it did have an issue in the past with the idle sweeping up and down about 500rpms or more and would stall "some" times but, it has not done that in awhile.

Plugs, wires, rotor, cap, fuel pump, FP regulator, EGR valve were all replaced in September. Cleaned IAC and pulled tuning valve to check for any washing in the intake and all looks good.

I have included a video to show what I am talking about.

Blazer Shutdown - YouTube

 

i bet if you were to take off that homemade intake and put it back to stock it wont do it anymore only because its more restrictive. any vehicle that ive had with an after market intake has made that sound. to me thats a normal healthy sound means you got compression and vacuum.