ok- I love my car but it is making me crazy. The engine has been pinging, tsb states knock sensor issues. I pulled the intake and replaced both sensors. Also their is a tsb about a computer flash update. I use to get 350 mp tank (3 months ago) now i am down to 300. No ses light or modifications, just a flowmaster. I called the local ls1 guy for a flash, he tells me converters are probably blocked, i did get the letter, dont want to end up with huge repair bill. Do you think that can cause the pinging???? I have 84,000 2000 Z28 auto. I replaced fuel filter, cleaned intake and fuel rails, use high octane gas, pinging goes away every time i use seafoam but next time i fill up it's back. I also get a "click click" first time i put it in reverse every day. Any idea?????