QuestionQUESTION: I have a 2001 Toyota celica, with about 136k miles. My check engine light has been on for quite some time, and the code came up as random misfire. I've replaced all 4 spark plugs, and coil pack number 4, but the code still comes up. I've had it checked by 2 mechanics, and they determined that its not the coil pack, spark plugs, cylinders, fuel injectors, or compression. I noticed that the CEL will flash when I accelerate, which indicates when the misfire is actually occurring, right? I've considered the MAF sensor, but I thought that there is a specific code for that issue. What could be the problem?
ANSWER: I will look into this but first I would need to know what code numbers you are getting,is it only getting a P0300 code or are there more specific codes? Yes the engine light is flashing due to the misfire, when this happens over a prolonged time the catalityc converter can be damaged.
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QUESTION: I believe the code is P0304.
AnswerThanks for the reply, that's a code specific to the #4 cylinder, you stated "they determined that its not the coil pack, spark plugs, cylinders, fuel injectors, or compression". Also, the spark plugs and coil pack were already replaced, I don't have a way to verify what the two mechanics tested and how they arrived at the conclusion that basically everything is ok but if it were you wouldn't be having this problem. I suspect a couple of things here, a bad injector or a bad engine control module(ECM) or a computer or injector ground connection. The pulse voltage from the ECM to the #4 injector should be checked, if the voltage to the injector is correct then I would replace the injector, the injector can make an operating noise but still be defective so that test is not conclusive
