www.iFourWinns.com

5.7l GSI makes a ticking rattling sound at WOT. Been running fine and only happens at WOT and a little under it and that is all. Oened it up once and it wanted to over rev like I had the wrong prop, but just did it once, so not sure if the vdo gauges screwed up momentarily since then its been fine, but could be a possible sign of drive troubles...what do you think?

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2000 235 Sundowner
Previously 2007 Horizon 190
2004 Chevy Avalanche Z71

a Rattling sound could be Detonation. Here is what Wikipedia says. "Knocking (also called knock, detonation, spark knock or pinging) in spark-ignition internal combustion engines occurs when combustion of the air/fuel mixture in the cylinder starts off correctly in response to ignition by the spark plug, but one or more pockets of air/fuel mixture explode outside the envelope of the normal combustion front. The fuel-air charge is meant to be ignited by the spark plug only, and at a precise time in the piston's stroke cycle. The peak of the combustion process no longer occurs at the optimum moment for the four-stroke cycle. The shock wave creates the characteristic metallic "pinging" sound, and cylinder pressure increases dramatically. Effects of engine knocking range from inconsequential to completely destructive. It should not be confused with pre-ignition (or preignition), as they are two separate events."
Not a good thing to have happen.

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Troy
2008 Centurion Avalanche
1994 Four Winns Horizon 180 SE 5.0L OMC Cobra (Sold)
2002 Ford F150 Harley Davidson Edition (http://www.nhtoc.com) 378 hp & 465 tq at rear wheels
2008 Honda Accord EX-L w/Nav