Motorists who use automotive diesel oil and ultra-low-sulphur diesel (ULSD) are set to see a significant increase in prices at the pump as Petrojam has announced changes to its pricing mechanism for those fuels, citing rising global oil prices and the financial impact recent market volatility has had on the state-owned oil refinery.In a statement issued today, Petrojam said the maximum pass-through of price increases or decreases for automotive diesel oil and ULSD will move from the current cap of $4.50 per litre to $12.50 per litre.