I hear about guys chasing these all the time so figured I would post. I made a long trip last week in the mustang and kept hearing this faint thunking from the trunk area. Checked my shocks, amplifier, spare tire etc and couldn't find anything so this afternoon I was pushing down on the rear quarters trying to find the sound and happened to push the trunk lid. Bingo! A VERY slight amount of play in the catch was the cause. Adjusted the catch on the chassis side (lower, not trunk lid side). Loosened the two catch bolts and moved it downwards a tad to tighten it up.

 

that's actually good to know, for future
reference.....

 

I thought it was your trunk monkey banging in the lid to tell you that you needed to make a beer run, lol.

 

 

LOLOLOLOL! Go trunk monkey GO!

 

Thats my favorite trunk monkey episode..."road rage guy" gets the crowbar treatment....priceless.

 

Car thief is the best.
Being thrown off the bridge after being clobbered FTW!!

 

Thanks for posting this. I think I may have the exact same problem and I thought it was the speakers, but I will check the trunk first.