Previously neglected '96 Max with 242k miles. I plan to use a whole can of oven cleaner and power wash the carbon build up. The build up is bad enough to the point that the evap vents are clogged. Do you guys have any other suggestions? No, I'm not going to torch it. That sounds like an insane idea.

 

I usually soak mine in Berryman Chem Tool and Carb cleaner (the kind that comes in a gallon bucket) to help melt the carbon. I get a plastic tub and use a couple of gallons. The worst I've seen was on a 98 model where the entire EGR tube opening was closed off due to a thick layer of carbon. I had to take a chisel to break it loose to open a hole so the Berryman could work its way in.

 

I’ve always just gotten them sand/bead/soda blasted.

 

Sand and beads in an intake manifold creeps me out. Id be afraid of left over stuff getting sucked into my well maintained engine.

I'm old fashioned. I like to pour a mixture of 10 parts kerosene to 1 part Dawn dishwashing liquid into the passsages. for a while to loosten crud. Then I shove a bottle brush into the passages. I use that to scub for a while. Then I use my garden hose and lawn sprayer for the final rinse.

I don't even bother unless there are a lot of deposits.

Only the passage from the egr really matters.