LOL ..

P0171 combined with P0174 is almost always the pcv line, usually the 90% rubber boot on the back of the intake, also check the line from the vapor management valve next to the power brake booster, the one with the green clip gets toasty near the EGR valve. P0455 could be a bad or loose gas cap - could be something else. P0401 could be DPFE or the vacuum regulator solenoid controlling the EGR or it could be plugged ports, burnt dpfe hoses or or or ..

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