Sounds VERY much like fuel filters (you mean "kangaroo petrol", right??
Even if filters were changed, some little piece of )(*&*&$&%$# could have blocked them. I once had to replace 3 fuel filters in that same number of weeks due to really bad gas (not on MB, thank God!)

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1985 190D 2.2l Sold-to Brother-in-law
1996 Mustang 3.8l -"thinks it's a sports car"
1988 Grand Wagoneer - Sold (good home)
1995 Grand Cherokee Ltd -"What was I thinking??!!"