Thread: Clunk/pop noise on accelerating/braking no one can diagnose

Hey guys, my 03 SE has been driving me crazy with a noise on moderate acceleration from a stop and moderate to hard braking, noise seems to come from drivers side front. No noise turning, on bumps, no vibration.
New parts I installed in last 2 months:
Front padS (Bendix), rotors (AC Delco)
Lower mounts (trans/engine)
Struts (Moog sent back due to noise on bumps, Monroe installed nice and quiet on bumps)
Drivers side cv axle
Previously about year ago installed performance upper dog bone inserts for less engine movement and new sway bar bushings
Few years back: upper and lower control arms with ball joints and bushings
Still clunking
2 shops have told me nothing loose etc to cause this
I did notice play between lug studs and rotor, I have a video but have to figure how to convert file from mp4 to attach.
Car has just surpassed 300k and is good daily driver but this noise has got me stumped, any help appreciated!

Here is the video i promised, is this normal? Maybe source of my noise.

2003 Pontiac Grand Prix Clunk - YouTube

Check your subframe bushing to body mount bolts, make sure they are tight. Also, check rack and pinion mount bolts, and lower control arm mount bolts. All these places gave me clunks at one time or another.
Cracks in the subframe can cause clunks but not common, unless car was in a crash at one point in its life.

Ever since I put those red inserts from ZZ Performance in the upper mounts, engine movement has calmed down quite a bit plus lower mount is solid now not hydraulic. Thanks for info on rotors, I couldn't figure that being a problem considering AC Delco parts. I'll check sub-frame and other parts Quicksilver mentioned. Gonna check torque on lug nuts too. Thanks for input guys.

Originally Posted by 2003GrandPrixSE

Ever since I put those red inserts from ZZ Performance in the upper mounts, engine movement has calmed down quite a bit plus lower mount is solid now not hydraulic. Thanks for info on rotors, I couldn't figure that being a problem considering AC Delco parts. I'll check sub-frame and other parts Quicksilver mentioned. Gonna check torque on lug nuts too. Thanks for input guys.

I had a similiar noise, the metal brace that is above the air box in the engine compartment was loose. the noise was a random creaking noise. good luck