An investigation of the effects of metal-based fuel-borne catalysts on the loading and regeneration performance of Diesel Particulate Filters (DPFs) installed on a test vehicle is presented. A test protocol that comprises regeneration attempts at steady state speeds following a loading phase for about 100 km was applied for the performance screening. None of the additives tested led to a complete regeneration of the filter under normal driving conditions. This was possible only if engine operation was modified in order to increase exhaust temperature. Methylcyclopentadienyl Manganese Tricarbonyl (MMT) in the higher concentration mixture in the fuel was found to be the most effective of the additives tested in terms of regeneration onset temperature.