Fuel Additive

Fuel additives are the bottles you pour into a full tank to clean injectors, lubricate the upper cylinder, or chase down a specific gripe like rough idle or hesitation on cold starts. Useful as a periodic maintenance dose (every few thousand miles) or as a targeted fix when symptoms point at carbon buildup or water in the fuel. Read the label — some are for gas only, some are diesel-specific, and an ethanol-treatment additive does a different job than a detergent shot. Add right before filling up so it mixes properly.