2005, 997.1, C2s with 32000 miles.

as of last week, I noticed after cold start in the morning, and after driving it for a minute, coming to a stop, makes strange sound, increases and decreases with the rpm, while in gear or out of gear, even at a complete stop.

This resolves after driving for a few minutes, so probably only happens when its cold. NO lights have come on, I will take it in to get checked and do a visual in the next few days.

But it is my daily driver, and this has only been happening, starting the past few days.

Any suggestions would greatly be appreciated, if anyone had the similar experience

W

 

Too vague.
What sound? Humming, belt squealing, scrapping?

Maybe a recording would help.

 

Sounds like ignition problem. Could be spark plug/wire/coil one of them is on their last days.

First thing to do is to read your faults, you should have a knock/missfire reading, but even if you do not have a knock reading this is what I would do:

I would change oil, filter (since you are up anyway) and sparkplugs. Look at the sparkplugs, if one looks moist, that is the one that has a coil problem. IMO if you have one coil with a problem might as well change all of them, (USD 280). But if you do not want to do that, buy one coil and replace the one you suspect.

http://www.pelicanparts.com/cgi-bin/...%2520Each%2520


If that does not work take it to the dealer, and least what I suggested is just something you should probably do after 7years at 30k anyway

Bare in mind that a bad coil, no ignition on one cylinder, will ruin your catalytic converter over time, and that's expensive.

 

Whole host of things could be going on here. Is the car completely stock ? Throttle body, plenum, airbox or any other mods done ?

Does the car idle smooth or is it rough ? Could be an idler pulley, water pump bearings to name a few....

These cars are very sensitive to any kind of vacuum leaks and will significantly impact how the car runs and sounds.

 

Thank you guys for all the helpful suggestions!

The car is completely stock.
The car drives perfect, idles just fine.
This was first heard a week ago, after a cold start (not completely warmed up) then coming to a stop, I would hear it, so I thought maybe the braking system.
This morning I rolled down the windows and tried to listen to it better, so even at a stop, out of gear (manual), while the engine was idling, it would resonate up and down with the rev. So I'm assuming its a belt/pulley related issue. The sound is a grind, but deeper than break sound.

Once I drive it for a few minutes this is completely gone, even coming to a stop or go. After a few hours of not driving it, I will expect to hear it again, and I will let you know this evening. I cannot take it in until Friday or next Monday.

 

Apologies, I understood you wrong the first time I though your RPM was erratic, going up and down, you are saying the noise goes up and down as you change rpm. OK .

I would be very cautious (and diligent) with any strange noises coming from a 2005 P-car, the IMS bearing failure is not out of the question, specially with cars that are not often used (low mileage/short trips) and have had long oil interval changes (10k miles).

I would ask for someone to rev your car while you search for the source of the noise, if it comes from below, close to the where the transmission joins the engine, then IMS is a possibility, and you should seek professional advice. Could also be a 100 different insignificant things, that is why an experienced ear mighT really help you.

http://www.pelicanparts.com/techarti...MS_Bearing.htm