"hissing" sound on acceleration

[Shaun Tucker]

Hey guys,



I've been having this really annoying hissing sound upon acceleration. It only exists between 2000 - 2500 RPM (the range where i do the majority of driving) and sounds like it is coming from behind the dashboard. When I roll my window down I'm pretty sure I can hear it outside too. (Its been really REALLY cold lately, so I havent had it down much).



I recently cleaned the IAC, the Throttle body, and replaced the PCV valve.

I had a Tranny flush, coolant flush, and oil change and fuel filter change performed a couple months ago.



This hissing sound started shortly after that work was performed.

I've done a search on this issue, but there are no conclusive results and those that experienced this "hissing" sound before had it happen while they were coasting or just after accelerating, not during acceleration.



What should I check for (cracked elbows? where, which ones)?

Could this be due to my less-then-stellar mechanical skills while cleaning the IAC or throttle body?



Any suggestions would be appreciated.

THX



st

 

[Todd Z]

Sounds like the intake hose or the PCV hos is not clamped or fell off.....



Look on the drivers side of the back of the engine where the PCV valve is.... Follow that hose to the TB if all good, Look at the intake hose and the intake breather connection...



OR a hose to the vacuum controls came off under the dash or hood..



Todd Z

 

[scott degroot]

Usually a vacuum leak will be loudest on decel or at idle. When you accelerate vacuum drops off significantly so if it were a vacuum leak I would expect it to become quiter during accel.

 

[Shaun Tucker]

Thanks Guys,



Todd you are a life saver. I will check those connections when I get home from work!



Love this place!



st