The 2018 Infiniti QX60's check engine light with P0455 indicates a large EVAP system leak, while hesitation may be related or coincidental. Understanding how the EVAP system might affect driveability helps determine if both symptoms share a common cause.
EVAP System and Driveability
The EVAP system captures fuel vapors and routes them to the engine for combustion. P0455 indicates a large leak in this closed system. While EVAP issues are primarily emissions concerns, a stuck-open purge valve can affect air-fuel mixture, potentially causing hesitation. However, the symptoms often have separate causes.
P0455 Common Causes
Loose or missing gas cap is the most frequent cause—check this first. Cracked or deteriorated EVAP hoses allow vapor escape. The purge valve or vent valve may be stuck open. Charcoal canister damage from fuel overfilling creates leaks. The fuel tank or filler neck may develop leaks.
Hesitation Considerations
If hesitation coincides with P0455, a stuck-open purge valve is suspect—it can lean out the engine. However, QX60 hesitation may result from unrelated causes including transmission programming, throttle body carbon, or fuel delivery issues. Determine if both symptoms appeared simultaneously.
Diagnostic Approach
Start with gas cap inspection and replacement if questionable. Clear codes and drive to see if P0455 returns. If so, smoke test the EVAP system to locate leaks. Address hesitation separately if it persists after EVAP repair, as CVT-related hesitation is common on this platform.