Rythmic Rumbling After Cold-start

[morg96ls400]

Hey guys I was wondering if anyone has experienced this problem or has any idea what could be causing a rythmic rumbling (every other second) after a cold-start. After the car warms up its undetectable. I replaced PCV valve and grommet but this did not remedy the problem. I was told that the EGR pipe has a crack in it and needs to be replaced soon, could this cause it? Also, whenever I accelerate there is a noise coming from the engine that sounds like gas gurgling. maybe this is the sound caused by the EGR pipe crack? No clue!

Thanks for the help

-Dan

[SKperformance]

Get the pipe welded either way then you can start finding other problems if any.

[alsalih]

I also had the rhythmic rumbling on my 98 LS especially during cold mornings and what cured it for me was simply replacing the transmission mount. This V8 engine as most other V8's has an oscillation at several engine speeds and with an old stiff rubber mount this vibration can become noticeable. However, I still have this gurgling sound. It appears to come from the transmission at a specific engine RPM (about 800). I've just learned to ignore the gurgling sound as the car drives fine and it also goes away once the car has warmed up. In your case I would repair or replace the cracked EGR pipe, and replace the transmission and engine mounts. If anyone has any idea on what might be causing this gurgling sound please let us know!! By the way I have replaced the transmission fluid/filter, fuel filter without any change to the sound.

[lovlex]

a friend's car does the same thing