The tube that is not easily accessed is not the vac hoses in the front of the engine.
That tube will be a large metal tube/pipe coming from the EGR and going to the intake at the head and it goes across the the rear of the engine..They block with carbon where the tube meets the head port that the egr gases flow through.
The vac hoses in the front of the engine do not block up, they crack or split open and they only transfer vac supply to operate the egr valve..different hose altogether.

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A Dalton