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2005 Monte Carlo Hesitation During Acceleration with P0455 Emission Leak Code

Model: 05 Monte Carlo Fault Code: P0455 Posted: 2011-02-14 12:27

I own a 2005 Monte Carlo with a 3.4L V6 engine that has been exhibiting hesitation specifically during acceleration over the past few months. The check engine light activated and displayed Diagnostic Trouble Code (DTC) P045- Emission Control System Leak Detected (Large Leak). Multiple sources suggest that an evaporation system leak is unlikely to directly cause engine hesitation, yet the code persists after clearing it. After a few weeks, the same P0455 code reappeared. I've already ruled out common issues like spark plugs, plug wires, and coil packs, so I'm seeking input on whether there's a connection between the evaporation system leak and the performance issue. Any insights or recommendations would be greatly appreciated.

Related fault codes
P0455
Comments (4)
Anonymous 2011-02-15 20:12

DTC P0455 indicates a large leak in the evaporative emissions system, most commonly due to a faulty gas cap or evap vent solenoid. A professional smoke test is recommended to accurately locate and confirm the source of the leak.

Anonymous 2011-02-16 09:03

Can a bad gas cap actually cause engine hesitation during acceleration? I've heard it's more related to idle or fuel pressure, not throttle response.

Anonymous 2011-02-26 18:46

I have the same symptoms. The dealership diagnosed it as a vent valve issue and replaced the camshaft position sensor, spark plugs, and wires—no improvement. They also suggested a possible camshaft actuator failure as a root cause.

Anonymous 2011-02-26 19:12

You're likely dealing with two separate issues: P0455 is related to the evaporative emissions system and does not directly affect engine performance. For accurate diagnosis of the evap leak, a smoke test by a professional is advised. As for the hesitation during acceleration, it appears ignition-related—start troubleshooting there first.