So after I have been driving for say 5-10 minutes and I pull up to a red light I hear a knocking sound very similar to if someone knocks with thier knuckles on a 2 by 4. The sound happens every 8-15 seconds while idle. It sounds like it's coming from behind the passenger seat underneath. I see to only hear it at night but that's most likely because it is quite then. When I pull away no sound at all. Any input would be loved.

Thanks,
Nick

 

Sound like either driveshaft or exhaust whacking on something.

 

driveshaft center support bearing or driveshaft flex disk

my guess

 

Likely only hear the drive shaft coupling if you were moving. He hear ist when stopped.
I'll put my money or an exhaust bracket failure.


franc

 

Sounds like exhaust if it's happening at idle at stop cannot be Drive shaft.
I have seen vibration knocks in exhausts when at a slow RPM or when just barely letting out a clutch.
If you have the 6 speed from a stop low RPM put an ever so slight drag on the clutch and if there is a change in the "Knock" it's 90% exhaust loose.
Mike

 

My bad... I read too fast sometimes, I though he said while slowing down.

Exhaust hitting sounds like a possibility.

 

see if you can take her somewhere where they have a car lift...get under there and shake your exhaust system back and forth to see if it is hitting something at idle.......

 

Alright, will do. Thank you so much for the info. Any other possible ideas?
No stick here btw, it's my srt-6

 

Fuel pump and regulator is under pass seat and if it is vibrating just right................... Woody

 

Have you checked under the car for any kids that you may have accidentally run over and are trying to get your attention? That's a pretty common problem from what I hear.

 

My vote: Exhaust hanger rubber bushing failing. Vibration squashes bushing too much and making metal-2-metal contact.

2nd vote: driver needs medication adjustment for schizophrenia so that he/she stops hearing noises and cars speaking to him/her in tongues.