My front bumper cap (black textured plastic) is (or should I say "was") so faded that it looked like gray Z71 plastics. I tried countless products, Armor all, Tire wet, Mothers Back to black, peanut butter, and even motor oil. Each was only a temporary solution for maybe 2 weeks at the most. I can't say I ever tried Pledge though. But what I have been using for the past few months (with only one application a month, even with rain and washing it) is Adams Super VRT . The VRT stands for Vinyl Rubber and Trim.
This stuff works wonders on black plastics and trim, and tires too. Its a low to medium gloss, so it doesn't make it look wet, just looks clean and "new looking".
Here is my bumper the very first time using it, with a section still untreated.