Bora V5 feels less powerful than it was before

[EdwinConan]

Hello Volks

On Sunday, after I visited the Day of Volkswagen at Yarra Glen, I decided to go for a little drive around the mountain road of Healesville and Kinglake, where there were a lot of bikers. And the Bora felt normal.

But on Monday, the car starts to feel a bit less powerful than it was on Sunday, in terms of acceleration that is. It doesn't get up to speed as quickly as it was last week.
I thought maybe it was just me being used to the 80km/h and 100 km/h speed limit that i did on Sunday. But then I start to notice a very fade hissing noise hidden in the normal engine noise. When accelerating, the I can hear the hissing a bit more, but still quite hidden. Is this hissing noise in anyway link to the car feeling less powerful? Or is it just me being too suspicious, where in fact there is nothing wrong? Or is it just the air this month is warmer, so the engine is less efficient?

[Neroo]

you could possibly have a cracked intake/exhaust gasket somewhere would explain the probz you have been having but yeah no way to shorely know without being there =]

[mk5fsi]

The hissing noise, is most likely a vacuum leak, or like neroo said a crack somewhere on the intake. Does the car idle smoothly?, and how is your fuel consumption?, if its bad, that means it's running rich, which would be explained by a leak or crack somewhere. A car that is running rich means that more fuel is injected to compensate for the increase in air coming into the motor.

[EdwinConan]

The hissing noise, is most likely a vacuum leak, or like neroo said a crack somewhere on the intake. Does the car idle smoothly?, and how is your fuel consumption?, if its bad, that means it's running rich, which would be explained by a leak or crack somewhere. A car that is running rich means that more fuel is injected to compensate for the increase in air coming into the motor.

The car idles smoothly, and the fuel consumption seems normal as well.

[Adzismad2]

Its sounds to me like it is more exhaust leak than intake.

If you've lost back pressure the car will defiantly feel like it has no power at all. Run the car and see if you can smell fumes in and around the engine bay, also check under the car for leaks and cracks in the exhaust itself

Good luck

[EdwinConan]

I took my V5 to Volkspower, the guys didn't found any leak in the intake or exhaust, so they changed the MAF meter, now I've got the car back. I was very impressed that when I asked them to check the engine noise if it's normal, they really checked it, and found a very very fade noise that only come up when you put your hands on the metal bit of the air intake manifold, but they couldn't work out why the noise is there. I can hardly hear it.

I finally work out what the hissing noise is. It acutally the sucking noise when I press the gas paddle. Everytime I put my foot down, it makes a sucking noise and the plastic bit of the intake manifold (the bit that links the holes from air filter box to the metal bit of the intake manifold) changes shape ( I mean pop up a bit). Is this sucking noise normal? Do your V5 or V6 cars has this noise as well?