Spark Plug Replacement in San Marcos, TX

About This Service

Spark plug replacement keeps your engine running smoothly. New plugs improve ignition efficiency, combustion, fuel economy, acceleration, and reduce misfires while lowering emissions for reliable long-term performance.

Spark plugs ignite the air-fuel mixture in each cylinder thousands of times per minute. As electrodes wear, the gap widens, ignition timing becomes inconsistent, and combustion efficiency drops — resulting in misfires, rough idle, reduced power, and higher fuel consumption. Fresh plugs restore clean, consistent ignition across all cylinders and are a foundational part of any tune-up or scheduled maintenance interval.

• Restores consistent ignition and combustion efficiency
• Eliminates misfires and rough idle
• Improves throttle response and fuel economy
• OEM and premium iridium/platinum options available

At Riley Auto Care & Transmissions, we've been serving drivers in San Marcos and throughout Central Texas since 1978. Our certified technicians use the latest diagnostic equipment and quality parts to get your vehicle back on the road right the first time.

We'll give you an honest assessment and a clear written estimate before any work begins. No surprises — just straightforward service you can trust.