Started my P-car this morning and for the first few miles of driving I could hear from the engine a low frequency buzzing sound when accelerating, that would intensify as I got closer to ****ing. It pretty much disappeared once it was warmed up.

It goes in tomorrow for a 15K tuneup (the big one!!), is this the valve chatter I've read about? Or is this another thing to add to the list of "can you check this out" things that will add to my ever increasing final bill! Thanks
Adam

 

Sorry!!

What I meant was of course "shifting" wonder how many times that typo has happened on this board....

Adam

 

Same thing with mine. Cold weather just started and so did the noise. Sounds like it is coming from the right rear area? '84 911

 

Yeah that sounds about right. But it must be only when it is stone cold, b/c I took it out for a spin during lunch today and there was no buzzing sound after sitting for about 3 hours.

Adam

 

Yes, when mine is hot no problem. I am still trying to trouble shoot.

 

Hey guys,
I noticed the same thing in my 85 the last two nights. Going home after work at 3am it was under 40 outside and car had been sitting for 12 hours. Same buzzing sound you guys are mentioning, goes away shortly after car is warm.

I was curious what it was also, have not looked into it yet.

 

It's the ambient air valve.

 

Yes, it lets hot air from the oil tank/ crankcase prevent the throttle from icing open in cold weather.