QuestionQUESTION: Hi Travis, got your answer to my question about sputtering at 4krpms. My car is a automatic so it shifts whenever. It seems to shift around 5k rpms on its own. It evenwill at 6k+ if I keep my foot in it. The gas is ok and it does this more once its warmed up. could it have anything to do with the vtech system. I don't know anything about that system.
ANSWER: Ron, any check engine lights on? Or sporadic check engine lights, meaning coming on then going off? The VTEC system is an entirely different system that is regulated by the engine computer. The VTEC system is not accessible until the engine reaches a certain temperature. VTEC ranges should be between 5000 - 5500 rpms and stay there until redline continuing throughout the gears. It is possible there is an issue but doubtful considering VTEC problems will throw a check engine code 100% of the time. I was also thinking maybe 1 or 2 of the O2 sensors could cause this but they will throw a check engine code too. If you are not getting a check engine code this has to be a fuel issue. Is the sputtering coming from the motor or is the transmission 'sputtering'? Let me know in a follow-up question.
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QUESTION: Travis,check engine light will come on when this happens then go off after awhile if I keep it under 4k. I barrowed a scanner from a friend it came up with p0300 which is misfires. It also came up with p1259 however I was unable to find out what that code means. Any help would be great. Thanks for all your time and help on this so far.
AnswerRon, P0300 diagnostic code indicates a random or multiple misfire. If the last digit is a number other than zero, it corresponds to the cylinder number that is misfiring. A P0302 code, for example, would tell you cylinder number two is misfiring. Unfortunately, a P0300 doesn't tell you specifically which cylinder(s) is/are mis-firing, nor why.
Possible causes - Faulty spark plugs or wires, Faulty coil (pack), Faulty oxygen sensor(s), Faulty fuel injector(s), Burned exhaust valve, Faulty catalytic converter(s), Stuck/blocked EGR valve / passages, Faulty camshaft position sensor, Defective computer.
If there are no symptoms, the simplest thing to do is to reset the code and see if it comes back.
If there are symptoms such as the engine is stumbling or hesitating, check all wiring and connectors that lead to the cylinders (i.e. spark plugs). Depending on how long the ignition components have been in the car, it may be a good idea to replace them as part of your regular maintenance schedule. I would suggest spark plugs, spark plug wires, distributor cap, and rotor (if applicable). Otherwise, check the coils (a.k.a. coil packs). In some cases, the catalytic converter has gone bad. If you smell rotten eggs in the exhaust, your cat converter needs to be replaced. I've also heard in other cases the problems were faulty fuel injectors. Random misfires that jump around from one cylinder to another (read: P030x codes) also will set a P0300 code. The underlying cause is often a lean fuel condition, which may be due to a vacuum leak in the intake manifold or unmetered air getting past the airflow sensor, or an EGR valve that is stuck open.
Code P1259 - The simplest check is to make sure the engine oil is not low. If its a quart or more low, this code can set. If it's normal it might be the v-tec pressure switch. Thats the most common cause. You would need a scanner with data list read out to check it.
