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Why does your 1987 Pontiac firebird 50 4bbl make a loud rattle noise during warm up when at full throttle only for a few mins then goes away but its a loud rattle that don't sound right?

Answer

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October 09, 2005 10:21PM

On many engines the engineers use redirected exhaust gases to quickly warm-up the engine. The valve that redirects the exhaust gas is controlled by a bi-metal spring and the valve assembly can wear out over the years and begin to rattle. It's usually on one of the exhaust manifolds. If you can find it, see if you can rattle it and if it makes a similar sound to what you're hearng.