engine tapping ...oh no

[IndianaVX]

ok,
my engine runs like a sewing machine...smoothe.....until tonight.
i drove to town, and picked up my brother, and while sitting in the driveway, i heard a faint, rapid tapping, and it seemed to be comming from the drivers side, back by the firewall. i reved it just a tad, and the tapping went away. so we went down the road just a bit, got some drinks, and while sitting there,(he went in), i checked my oil, which was just a hair low, but no tapping, so i grabbed the cable and reved it a bit, and the tapping returned, but just briefly, reved it again, and it didnt increase or get louder, it just quit, and i havent heard it since...
what should i be checking, help me, i am scared to death. its not loud, it almost sounded like when we were kids, we would put cards in the spokes of our bikes to make em sound cool. well, it kinda sounded like that except more metallic.
it sounds like a valve tapping, but only for a few seconds, not constantly.
YOUR HELP PLEEZE!!!

Thanks
david

[Joe_Black]

Is it a sort of ball-bearing-on-plate type of tapping? Or ball-pien-hammer-on-steel-bar tapping? What kind of oil are you using (brand, synth or dino, grade) and what's your local weather during this tapping?

[IndianaVX]

thanks joe for taking intrest...........
i would say, ball bearing on plate, or glass, rapid tapping, for just a few seconds, like ten or so, then i reved, and it went away. when the rev idled down, it was gone. it was evident enough that my brother, who knows nothing about engines, said "that sounded weird, you still have a warranty?" gulp......
using Mobil 1 10-30.....weather is warming up...it was about 60.

[Y33TREKker]

Are you sure it was a mechanical tapping and not an electrical snapping? Maybe something in the ignition?

[IndianaVX]

well, does the coil pack make any tapping noise??? i mean im pretty durn sure it was mechanical, but ive never dealt with these coils over plug setups..... i suppose it could be a rapid snap snap snap snap noise. also, when i started it up this morning, i heard the slightest of rattleing of sheet metal. dont think its related, but i dont know. havent been home again since this morning to check it out.....
thanks guys, ill keep answering if you keep asking....

thanks again,
david

[Tobert]

It could be valve adjustment. Mine taps like crazy, especially on lighter weight oils.