Nissan Repair: Engine Rattle or Knocking Noise at high RPMs, nissan frontier, auto parts store

Question
My 2003 Nissan Frontier has 79000 miles and is making a rattle or knocking noise when I go into passing gear or when the RPMs go higher on acceleration. It also seams to be worse when the temperature is hotter outside. This seemed to start after getting gas in Mexico. I assume it was bad gas. Can you tell me what this is and what I can do to fix it? THX

Answer
Hi David -

You may be right on the money. Engine "knock" is usually caused by low grade gasoline, or overheating. Assuming it isn't the latter, we can blame it on the gasoline. I assume you usually use 93 octane gas in your car. Using a lower octane fuel will cause the engine to knock, especially when going up hills, or as you describe.

An easy fix would be to purchase an octane booster additive. This can be purchased at any auto parts store.

Hope this helps, David -
aloha
calvin