Weird noise from engine when downshifting
 

1987 944 n/a. Can anybody help with this, when down shifting and getting to about 4000rpms there is a weird noise thats tough to explain. best i can explain is (errnt). It happens quickly and goes away. If i rev the engine to about 4000rpms and left off quickly, it makes the same very brief ( errnt ) noise. Any ideas before i start pulling things apart. Josh

Josh, is the noise coming from the rear of the car?

Heat shield? Exhaust related? check it out....

Josh,

If it happens while both downshifting AND reving to 4000rpm it could be as simple as a heat sheild as mentioned. Usually by the exhaust manifold. In a recent post, somewhere on the exhaust a crimp from the muffler or cat was loose. I have "body" noise on my "87 924S and cannot find it.

Does the sound appear to come from the top or bottom of the engine? I know this is next to impossible while driving but you may be able to duplicate the sound while under the hood.

Here is a link to a few noises and inspection:
http://forums.rennlist.com/rennforums/924-931-944-951-968-forum/350563-knocking-from-cam-tower.html

And this one is a suggested repair-"replace the front cam bolt" from mattdavis11.
Good pictures on this link:
http://forums.rennlist.com/rennforums/2854326-post1.html

GL
John_AZ