I believe the biggest threat is to the converters, for which lead is a 'poison' (blocks the active sites). One would think that an ECL would light up though if it was bad enough.... If no code, then he might have been lucky. As far as the engine is concerned, others may have more input on that as to effect but I believe that is minimal.

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GT Silver CS
1980 Honda CBX
2004 Suzuki SV1000
2006 Subaru Legacy
2002 Honda Insight