Incorrect spark plug gap can cause which of the following, leading to weak spark, misfire, and reduced engine performance?

Incorrect spark plug gap can cause which of the following, leading to weak spark, misfire, and reduced engine performance?

• A. Weak spark and misfire that reduces engine performance
• B. Increased fuel efficiency
• C. No effect on engine performance
• D. Stronger ignition leading to higher power

Answer: (A)

The key idea is that the spark plug gap must match what the ignition system can reliably jump. The spark needs to bridge that gap to ignite the air-fuel mixture effectively. If the gap is incorrect, the ignition coil may not deliver enough voltage to jump the larger gap (or, in some cases, the timing and energy of the spark are compromised). The result is a weak spark or a missed spark (misfire), which leads to incomplete combustion and reduced engine performance, including rough running and poorer acceleration. These other options don’t fit: increased fuel efficiency would unlikely come from a faulty spark—more often you see worse efficiency due to misfires. No effect is incorrect because ignition issues do impact performance. Stronger ignition leading to higher power would require a properly matched gap; an incorrect gap typically reduces, not increases, spark quality.

The key idea is that the spark plug gap must match what the ignition system can reliably jump. The spark needs to bridge that gap to ignite the air-fuel mixture effectively. If the gap is incorrect, the ignition coil may not deliver enough voltage to jump the larger gap (or, in some cases, the timing and energy of the spark are compromised). The result is a weak spark or a missed spark (misfire), which leads to incomplete combustion and reduced engine performance, including rough running and poorer acceleration.

These other options don’t fit: increased fuel efficiency would unlikely come from a faulty spark—more often you see worse efficiency due to misfires. No effect is incorrect because ignition issues do impact performance. Stronger ignition leading to higher power would require a properly matched gap; an incorrect gap typically reduces, not increases, spark quality.