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Compression gauge used as a valve tuner okay?

1.3K views 14 replies 7 participants last post by  malstrom  
The fact that it gets QUIETER when you open the throttle, instead of rattling just as loud, only faster, leads me to believe it's an exhaust leak/loose spark plug/blown Thermactor plug/leaking EGR valve (if a later model intake). Ill bet advancing the timing by 4-6 degrees will change the noise, too.