Hi,
I have 2013 Mazda3 with 120k miles now. Recently Engine check light showed up, checked with OBD2 scanner, had one code saying cylinder3 misfire, went to mechanics and 4 new spark plugs installed. Check engine light disappeared but came back again after few days. Diagnose with OBD2 scanner: same as before. What could be the reason? How could something (oil?) get inside and damage the new spark plug in such a short time? Note that I noticed excessive oil burning cause I had to add oil after 3 weeks since the last oil change. Have to go back on Monday to the same shop where I got new plugs. Any ideas what might be the cause or any similar experiences you guys want to share?
Thanks in advance

 

Swap the coils between cylinders & see if the misfire moves.

 

Thanks for your response! Mechanic switched the coils 2 and 3 . He checked again the plugs today and the result was the same. Number 3 plug fouled and number 4 has sign of contamination as it was before. So misfire didn’t move. What should I do now?

 

Mechanic said it may be an internal damage. Any suggestion how to deal with it? Taking apart the engine would be very expensive. Any good mechanic in SF,CA who can mend it? Thanks guys!

 

What is the actual code number?

 

P0303. Driving now 3rd day since number 3 and 4 plugs were changed (2nd time) and it shows yellow warning sign on OBD2 with yellow pdDTC. I think the check engine light is on the way, again.

 

Check engine light is back again!

 

Is you car a BL or BM chassis?

Engine = 2.0 MZD? 2.5 MZD or Skyactiv?

 

P0303

POSSIBLE CAUSE
• Erratic signal to PCM
― APP sensor signal malfunction
― ECT sensor signal malfunction
― IAT sensor signal malfunction
― MAF sensor signal malfunction
― CKP sensor signal malfunction
― TP sensor signal malfunction
― VSS signal malfunction
• Ignition system malfunction
― Spark plug malfunction
― Ignition coil related wiring harness malfunction
― Ignition coil malfunction
• Excessive air suction in intake air system (between dynamic chamber and cylinder head)
• Erratic signal to fuel injector
• Base engine malfunction
― Leakage engine coolant to combustion chamber
― Insufficient engine compression
• Fuel injector malfunction
• PCM malfunction

 

Skyactiv 2.0
OBD2 reader shows a $07E9 code after check engine light is on. Wouldn’t show the P....... code.