I purchased a Subaru Impreza 2009, AWD, 2.5 Ti about a month ago. A week ago, the check engine and traction lights came on steadily, with the cruise light flashing. I utilized a scanner to identify the error code, which read P0457. Consequently, I replaced the fuel tank cap, but the lights remain on. Despite this, I passed the emissions test a month ago, and I haven’t noticed any driving difference pre and post the appearance of these lights.

I've observed additional issues that might be related: upon pressing the accelerator pedal, I hear a ticking sound, and if I press too hard, especially when climbing, a rattling sound occurs. Nonetheless, the car performs well on both city and highways, and these sounds are not frequent and are avoidable. The fuel efficiency is normal for this model, yielding 19/20 mpg in the city and 26/27 mpg on the highway. I'm uncertain about a fuel smell, but it might be present if I press the accelerator too hard under certain circumstances, although it’s not strong.

I push the accelerator very hard but mistakenly using the manual model, so it turned to 4-5000 rpm but in a low speed in the morning, then after I drove in the highway for around 100 mils, then the check engine light came. I tested with a new gas cap, but the light was still on.

Looking for any suggestions!