my CEL light has been on for like 2 months now with misfire codes p0300 p0301 p0303 and p0304. i tried getting new spark plugs and new ignition coils and neither worked. about 2 months later i was gonna take a 2 hour trip (i knew my car was misfiring but took the risk cuz it was an emergency) and b4 filling up on gas i added fuel injector cleaner. 2 days later on my way back from work i noticed my CEL light was off. could just a simple thing like that make the misfires go away? or should i still be concerned about the misfires?

 

Misfires can be caused by dirty or malfunctioning injectors. You can also do a compression test to check if your cylinders are good.

 

leaking or damaged injectors can cause misfires. send them out to an injector clinic for them to get flow tested and cleaned. its only like $15-$18 an injector.

 

Could be a coincidence or maybe you did have a dirty injector. One major thing people dont think about is the MAF sensor. Do you have a K&N airfilter? Over time the oil does get on the maf and will cause misfires, this happened to me after 20k. I didnt have a clue what was going on and for the hell of it, I used maf sensor cleaner. This fixed it, really thought I had bad gas. Just saying make sure to check everything, sometimes there other things that contribute to issues I.e. weak fuel pump, fuel pressure regular, bad sensor.

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