Hello everyone, just bought my first 02 911 convertable with 85K miles on it. for the last month i been hearing a knocking sounds on the lower right side of engine. cars still runs great! and it only happens at idle and when engine is warmed. in the moring when idle is at 1000 rmp, there is no knocking sound. just last week i had a check engine light p0430 (right cat?)... I cleared it with a scanner and so far 1 week driving it has not come back.

possible valve lifters?? but sound is coming from underneath right side...

I also noticed the right side exhause pipe is getting more black vs the left pipe which still looks very clean. anyone has similar problem or any suggestions would be greatly appreciated!! thanks

 

Digging up an old thread in the hopes the OP will reply.


I am experiencing very similar behavior. A few weeks ago I started hearing a hollow infrequent knock that has become more regular and noticeable over time. 2 weeks ago the car threw a CEL for a misfire on cylinder 1, which was attributed to a cracked ignition coil that got wet during our FL monsoon.


I replaced all of the plugs and coils (as I just crossed 60k miles) and the car has run great for 2 weeks. Today on the ride home I threw another CEL with code P0430.


The most likely suspects are a bad Cat, or O2 sensor, but I am unclear if either of these would produce the knock I am hearing underneath the car. Hopefully the OP or someone else can shed some insight here...

 

too lazy to look up the code but if your cat is loose...it'll trigger code and you can hear a gradually increasing metallic/knocking noise

 

MY 99 had an knocking at idle, but I discovered the previous owner put on a lightweight fly wheel and that was my issue, I initially thought cats but when I Pushed in the clutch at idle and the knocking went way. It's a common mod on P-cars but when I changed the clutch I went back to the correct fly wheel and no knocking since. Good luck on sourcing the issue...

 

Here's a couple of threads to check out:

http://www.renntech.org/forums/topic...y&fromsearch=1

http://forums.rennlist.com/rennforum...e-noise-3.html

http://forums.rennlist.com/rennforum...-noise-ok.html