If it's a new vehicle the dealer puts their special shiny goo on it before delivery. I did a partial on my bro's new truck and it took both of us nearly 5 hours to get it "stripped" to my satisfaction. What a PITA!!!! Used S-W R7K156 followed by Orange Peel then 2 thorough hand washings with strong de-greasing soap.
I told him if he ever wants me to do this again tell the dealer do not pre-delivery prep. It took twice as long to clean than install.
Once you think you got it really clean do it again!