anyone ever have there ngk tr55's loosen up on them? installed them when i installed the long tubes about 500 miles ago. started ticking last week so i thought i had a header leak. to my suprise all the plugs were loose. some more than others. tightened them agian and no more tick. was just curious if this was a problem with the tr55's.

 

I had some stockers shake loose. It was maddening, my car actually died when they came loose, I tested everything in the ignition except to see if my plugs were falling out.

Have rough road surfaces by you? They were doing road construction on the road to my work, so rough roads over time shook mine loose.