weird noise when pressing the gas

[elach]

Hello everyone,

I am hearing a faint high pitch tone when I reach about 3000 rpms in fourth gear. I don't experience it in 1st, 2nd or 3rd gear, but once I shift to fourth and reach 3000 rpms I hear the high humming sound whenever I press the gas. If I take my foot off the gas the sound stops. It occurs in fifth and sixth, but it's harder to notice because of road noise. Any idea what this could be?

1999 996 C2 coupe

6 speed manual

80,000 miles

Thanks,

Ed

Edited August 7, 2010 by elach

[fbgh2o]

A couple questions

Where is the noise coming from, front or rear of car?

Is it a "whine" like noise that is proportional to road speed or engine speed?

It could be as simple as a belt slipping under load.

[wvicary]

Very hard to say but does the sound change pitch or volume if you turn the wheel slightly back and forth at road speed causing the vehicle to rock side to side? It could be the early signs of a failing wheel brng.

[elach]

A couple questions

Where is the noise coming from, front or rear of car?

Is it a "whine" like noise that is proportional to road speed or engine speed?

It could be as simple as a belt slipping under load.

It's hard for me to distinguish where the noise is coming from. I would guess it is from the rear. the sound is not so much a whine as it is a hum and it is not like it gets louder the faster I go. It is more or an occurring not occurring sort of thing. When I am in fourth gear or above at or above 3000 rpms, the hum occurs. so it starts at around 55 to 60 mph and is audible only when i am pressing the gas.

[demosan]

A couple questions

Where is the noise coming from, front or rear of car?

Is it a "whine" like noise that is proportional to road speed or engine speed?

It could be as simple as a belt slipping under load.

It's hard for me to distinguish where the noise is coming from. I would guess it is from the rear. the sound is not so much a whine as it is a hum and it is not like it gets louder the faster I go. It is more or an occurring not occurring sort of thing. When I am in fourth gear or above at or above 3000 rpms, the hum occurs. so it starts at around 55 to 60 mph and is audible only when i am pressing the gas.

Could be a belt tensioner beginning to go bad. Have you ever replaced either the idler pulley or belt tensioner?? If it were either pulley, you should be able to create the noise by reving engine with engine latch open and listening for the nosise with someone reving motor to 3000RPM as you state that is when you hear the noise.

Good Luck!! :cheers: My $.02 Demosan