[nadinehorneck]

Hello! My 2012 Nissan Versa engine light has been on for a couple months now. It is a 303 code with the 3rd cylinder misfiring. I went to a shop and the mechanic replaced the 3rd coil. The light turned off for ~1 month but then the same error code appeared. I took it back to the same shop and he replaced all 4 spark plugs. Unfortunately, that did not turn off the light and the mechanic told me I would probably need to replace the engine. Since the car is no longer worth much money he recommended that I get a new car. However, I am a student and cannot afford a new car in this market. I am really looking for some way to fix the problem. A friend of mine suggested that I replace the PCV valve, which I did but still no improvement. We decided to replace the 3rd spark plug again, because when we checked it was somehow already burnt black again. Throughout this entire time, the car has been using way more oil than it should and I am having to refill oil every 2 weeks. The misfiring seems to occur most when I am stopped at a light or stop sign. The whole car jerks back and forth. I am unable to bring it into a shop as diagnostics for this sort of problem are extremely expensive and many places aren't willing to take a look at my engine for less than $600. Has anyone had a similar problem or any ideas on how to fix it? At the moment we are thinking of just purchasing a used engine and finding someone who will put it in for cheap.

 

[Desert Rodent]

I think you need to know the overall health of your engine. I'd do a compression check.
You may also want to research "Piston Slap". There is some information on cylinder number 3 failing on these engines.

 

[PoMan]

Are the spark plug boots a separate component from the coils on this engine? You often have to order the boots separate. Do the boots have odd marks on them like the spark is escaping to the surrounding metal (and not getting to the spark plug). This is common thing. If the spark plug wells are filling with oil, the spark will also short out. Typically have to replace the valve cover or the spark plug tube seals to prevent those from filling with oil.

Also, aftermarket coils can be absolute junk. I'd buy a used OEM coil before I bought a new aftermarket.