I own a 2015 Sonic that's been started having issues last month with the engine vibrating when my car is either idling or at a red light. Two weeks ago, the vibrating turned to shaking where car quit in the middle of a downtown intersection and I had to get it towed. That time, the check engine light came on with P0340, which had to do with the camshaft sensor. Dealership claimed my timing belt was also bad though I had it replaced 50,000 miles prior. After those, a valve and a pulley, and the engine mount got replaced, my car was still misfiring.
The check engine light came on again last week, this time with trouble code P0171, which indicates a "System Too Lean", which means there's either not enough fuel or too much air. I fixed the light by screwing the air filter compartment that the oil change technicians left open and disconnecting the negative terminal. Then last night, the check engine light came on again with P0171, so clearly the air filter compartment wasn't the issue.
When the check engine light comes on, the car has been driven for a few hours at least, the engine is overheated though no exhaust or smoke problems, there's a rattling sound near the back of the engine, and the vibrations from idling get worse as the engine starts shaking. The second time this happened, my car almost quit again at a red light and it took me slamming the gas pedal to get it to move so I can reach an AutoZone that was still open.
Given the symptoms I mentioned, how do I diagnose the P0171 problem? I'll be taking it to a shop in the morning and someone I talked to thinks it's the coolant valve since my engine overheated each time and the coolant level dropped as a result.
The check engine light came on again last week, this time with trouble code P0171, which indicates a "System Too Lean", which means there's either not enough fuel or too much air. I fixed the light by screwing the air filter compartment that the oil change technicians left open and disconnecting the negative terminal. Then last night, the check engine light came on again with P0171, so clearly the air filter compartment wasn't the issue.
When the check engine light comes on, the car has been driven for a few hours at least, the engine is overheated though no exhaust or smoke problems, there's a rattling sound near the back of the engine, and the vibrations from idling get worse as the engine starts shaking. The second time this happened, my car almost quit again at a red light and it took me slamming the gas pedal to get it to move so I can reach an AutoZone that was still open.
Given the symptoms I mentioned, how do I diagnose the P0171 problem? I'll be taking it to a shop in the morning and someone I talked to thinks it's the coolant valve since my engine overheated each time and the coolant level dropped as a result.
