Last year, around the time winter was changing to spring, the VSC light started flashing on my 2009 Vibe, and the traction control light and check engine light came on at the same time. When they came on, the engine immediately started running rougher, then smoothed out a bit, but still was rougher than normal. I drove like that, got to work, turned off the car, and then when I turned the car on to go home later, everything was fine--no lights, everything running fine.
However, it did that intermittently for a few days with the lights coming on and rough running. But it went away after a few days of that.
This year, the problem has come back--same time of year--and it's much more frequent and worse (at one point, the car was practically shuddering from the rough engine). So I decided to buy an OBD reader and check the codes. The OBD shows code "P0351". In looking at that code on RepairPal (https://repairpal.com/obd-ii-code-p0351
), it says this:
Code: Select all
Common Problems That Trigger the P0351 Code
Defective Ignition Coil(s)
Defective Spark Plug(s)
Intake Manifold Vacuum leaks
Carbon buildup in the Throttle Body air passages
Defective Idle Air Control Valve or Electronic Body
Now, from what I've read, the first two are the most likely culprits. But my question is--if either the ignition coils or spark plugs were defective, wouldn't they cause the rough engine symptom constantly, rather than intermittently? During the intermittent times those three dashboard warning lights are off, everything seems fine, so I'm wondering if I should bother replacing the ignition coils and spark plugs, or focus on trying to run through the other three...?