I use Redline additive too. I put a couple of ounces in with every fill up. I'll also use it to fill the secondary fuel filter when I do a filter change. I've done a Diesel Purge on both my cars and felt little or no difference. I tend to agree with Wes that my injectors weren't dirty enough to feel the effects of the cleaning.

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LRG
1987 300D Turbo 175K
2006 Toyota Prius, efficent but no soul
1985 300 TDT(130K miles of trouble free motoring)now sold