The only fuel additive that I have used is Techron. It’s the original Top Tier product engineered to remove carbon deposits. Mopar sells a kit with three (3) branded products for this, it’s pricey but I know I can trust them. But I’ve recently learned about Liqui Moly additives and I’m considering trying one or two; it’s a Top Tier brand that is the most popular throughout Europe. They have a Valve Cleaner that seems to be excellent; my only concern is potentially contaminating an oxygen sensor. Has anyone used any of the Moly products? I only use Chevron or Shell gasolines, they have additives to prevent carbon buildup so I don’t even know if I need a “one time” boost in cleaning. Your thoughts and or experiences?