I guess thats a possibility, but I doubt it as it would've had to have been a pretty small screw or washer or whatever.

It could've gotten embedded in the cylinder... That happened to my brother in his old mustang.

1999 Mystique LS V6 Alpine CDA-9807, Rear deck sub, Opt. TB, K&N RU-3530/MAF adaptor, custom heatshield, FSVT 17's, SCT 4-program chip, Eibach's/ST200's, Hella Fogs...