I can answer your question. The 1998 to 2002 Firebird Formula, Trans Am, and WS6's came with an LS1 engine. Some of them have something called piston slap (which sounds more like a knock) is caused by too much clearance between the cylinder bore and the pison. It's worse when the engine is cold and lesses when it reaches operating temperature.
Thursday, June 18th, 2009 AT 1:41 PM