I have a 89 pontiac firebird Trans Am "GTA" 5.7L tuned port injected. About a week or so ago I changed the TPS. I started the car and it was sounding great and then it sounded like something got sucked into the intake and was flying around in there. It will make that sound and then stop for a few seconds then do it again. I pulled all 4 plugs on the drivers side and one of my plugs the tip is bent down and over. I turn the motor over without the plugs and it makes no pinging sound at all. Is it possible that something got sucked into the cylinder and bent the plug and exited the exhaust and the noise im hearing is from either the valve or piston hitting the plug? Or what could it possibly be and how do I check and/or fix the problem?? Thank You in advance for your time and help

 

It's possible.
Verification can be done either by pulling the head or by getting a boroscope and looking inside the cylinder.