When starting a cold engine that runs rough, what should you do?

When starting a cold engine that runs rough, allowing it to warm up is the appropriate action to take. Cold engines often perform inconsistently due to thicker engine oil and other fluids that haven’t reached optimal operating temperatures. By letting the engine warm up, the fluids circulate more effectively, reduce friction, and allow the engine components to expand to their proper operating size. This warming period helps stabilize engine performance and can reduce rough running.

In contrast, turning off the engine immediately may not address the underlying issue causing the rough running. Accelerating to stabilize can lead to unnecessary stress on the engine, as forcing it to run at higher speeds while still cold may exacerbate the problem. Checking the oil level, while important in general engine maintenance, will not immediately resolve a performance issue linked to cold starting.