A starter relay is a small component, but it sits at an important crossroads in the vehicle’s starting circuit. When it begins to fail, the result can range from a completely silent start attempt...

A failing thermostat can create two very different problems: an engine that runs too hot or one that stays too cold for too long. The most common bad thermostat symptoms include overheating, slow...

A transmission rarely fails without leaving clues. Slipping, delayed engagement, harsh shifting, shuddering, unusual noises, fluid leaks, burning smells, warning lights, and difficulty selecting...

A catalytic converter can fail without announcing itself in one unmistakable way. Depending on whether the catalyst has lost chemical efficiency, become contaminated, suffered internal damage, or...

An engine misfire occurs when one or more cylinders fail to produce normal combustion. Common engine misfire symptoms include rough idling, shaking, hesitation, jerking, loss of power, poor fuel...

A failing PCV valve can create symptoms that look surprisingly similar to a vacuum leak, worn piston rings, valve-seal problems, or even an ordinary gasket failure. The key is to understand that the...