Hmmm. Have you had the injectors checked? By hammering I meant clacking that is much louder than normal. Hammering is a sign of a faulty injector. Does the vehicle smoke at startup? If so, what color is the smoke?

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Chris

'04 ML500 - 53k, Inspiration Edition, Desert Silver
'11 Audi A4 Avant - Brilliant Black
'87 300SDL sold
'99 C280 Sport sold
'85 190E 2.3 sold