Chevrolet Repair Questions? Ask a Chevy Mechanic for Answers ASAP
Hello. My name is ***** ***** I will be assisting you today. First we'll discuss the codes... the first the are related. this is pointing to your evap system. The gas cap would be the first to get checked. This code usually means that your evap canister is malfunctioning or needs attention. Could be a leaky hose. The po300 and p0304 are related. They are letting you know that cylinder 4 is misfiring. When was the last time the plugs were changed? I would check the coil for that cylinder and the pigtail(connector) for that coil. P0171 means that you are running lean on fuel. This could be caused by a faulty evap canister or dirty fuel filter, fuel pump may be malfunctioning, or it could be the fuel pressure regulator getting clogged. You should have all these things checked.
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