Mystery Hiss

Hey guys I've been getting a really weird hiss sound from my b2200. It is only a short hiss not a consistent one lasting about half a second. It happens at the halfway point when releasing my clutch even if I'm in neutral. I also get the hiss when lightly pressing my gas pedal. The hiss sometimes continues as I'm pressing the pedal, sometimes not. I only notice it for the first 10 minutes of driving my truck in the mornings and then it seems to go away.
I assumed that it was some sort of vacuum leak so I went around my engine bay spraying carb starter to try to find any change in my idle - no luck. It does however sound to becoming from my engine bay.

A little about my truck. 1989 180,000Km. No A/C and no power steering.
Hiss has happened before and after these parts. - Weber 32/36. New b2000 head with all new valve train, new head gasket and intake gaskets. New timing belt and water pump.

Any ideas would be awesome.

Thanks

Sounds to me like either throw out bearing or pilot bearing. Also the slight his u hear on acceleration is probably just the Weber. Mine sounds like a cai.



Fred

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I noticed a different sound of the weber drawing in air then the stock one. However this is different and this hiss on acceleration was there before I installed the weber. I was hoping the weber would fix it.