Carbon build up

[Geoff Richards]

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<snip>
> According to a service bulletin, the 3.8l engine suffers from carbon
> accumulation on the back of the intake valve which significantly
> reduces performance. 

How to remove this carbon ?
Possible with the myriad of 'carbon blast' type of miracle cures,
you know the cans of cleaners etc,run 'em through the engine
while running or pull the heads?
Geoff