Modern cars are a complicated mix of electronics/ computers/ software controlling mechanical and non mechanical aspects of cars. Always make a checklist. Understand what all components are involved in the chain of a particular aspect. If you detected slush or dirty fuel, you should have checked the entire fuel system from A to Z which starts from your fuel tank, fuel filter/ pump, fuel lines, plugs, injectors and anything in the channel related to fuel. Then move ahead to other troubleshooting steps like Cat Converter cleaning, air cleaning element, clutch plate/ cable (if manual) and so on. Always get hold of a suspected end and work your way up or down to eliminate issues with that complete system.
