VooDoo
New Member
Check light comes on every 200 miles or so. Always clylinder 5. I have tried new plugs, and coil. Runs great otherwise. Anyone think it might be a injector or a ecu glitch? Input please.
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A bad O2 sensor or bad cat will not cause a misfire on just one cylinder.There are far easier ways to test a misfire without any tools.It would be a P0305 code. That's the OBD II code for a cylinder 5 misfire. It can be caused by one of the following....a bad spark plug, a bad coil, a bad injector, a burnt exhaust valve, a bad catalytic convertor, a bad O2 sensor. The first thing to check is the spark...pull the plug, if it's fouled by gas clean it and test to see if the plug is does indeed spark. In this case he replaced the spark plug with a good one. Next check the coil, use an OHM meter, if it's in spec it should be good. Once again he has already replaced that. Next check the injector, a noid light will tell if the wiring is working but a common check is to remove the injector from the affected cylinder and move it to another location (keep track of where you put it) clear the codes and drive until the problem repeats. If the problem repeats at the new cylinder (why you keep track) then the injector is probably leaking. If none of the above pan out you maybe have to drop the exhaust or try and take a peek inside the motor some way. Most vehicles will not throw a code for a coil if it's out of spec and the spark is just weak, and they won't give a code for an injector that is dripping unatomized fuel into the engine. Those codes only appear when there is a problem with the wiring that the computer can detect. It has no why of check for a mechanical problem with the injector or the OHMS of the coil.
A bad O2 sensor or bad cat will not cause a misfire on just one cylinder.There are far easier ways to test a misfire without any tools.
Try moving your injector like posted above. It it's starting to leak fuel in to the cylinder it will keep fouling plugs. Look at the next plug you pull. Changing the plug may fix it temp but if it's bad injector it may just take a while to foul the next plug.
champion platinumI just had a P0304-CYLINDER NO.4 MISFIRE CEL come up last week...
I installed six new spark plugs.
Problem solved!
BTW, what spark plugs did you use?