WS6_2000

I have a 2000 Trans Am with Headers and X Rumbler exhaust. I disconnected the EGR valve from the headers and plugged the hole in the intake manifold. The other day I started to notice that when I shut the engine off I hear a hissing noise, fairly loud, and Im not sure what it is. I dont remember it happening before but maybe it has always been there. Anyone have any ideas?

Fabian

iTrader: (5)

AC compressor? I remember a buddy of mine panicking about that and it was just the AC turning off...

71_firebird

I had this happen to me too, it turned out to be the MAF. When I removed it for speed density the noise went away. Mine had a little girgling sound mixed in too. This was on my dragster so the MAF was right in my face so there was no guess work. I've also had several vehicles make noise frome the A/C system on shutdown....

Lee

WS6_2000

so do is that a sign of the compressor going bad or thats just normal?

Fabian

iTrader: (5)

Normal I think. Mine does it and it works fine. Just the way it sounds I guess. Go out, run it, turn it on, shut the car down and listen.

Start the car back up, make sure the AIR system, hvac fan and AC are off and see if its any different.

87silverbullet

iTrader: (11)

Its normal. Its just the high and low side of the a/c system balancing out after you shut the car off and the compressor is not pumping anymore

themack56

iTrader: (70)

i dont think its the ac compressor, i did the ac delete, and i have that hissing noise, i know my maf is good, i also had the noise before the ac delete, so im pretty confident its not that, but every car is diff....

'91firebirdformula

iTrader: (3)

vacuum leak??

themack56

iTrader: (70)

its sounds like its coming from the intake, on my friends 97 ls1 z, does the same noise, so i think its nothing