P0300 code random misfire...
The first thing you want to know is, is the misfire truly
random. You need to scan it. You need to look at
Misfire Current Cylinder 1 through 8. If one or a few
stand out, you can follow that train of thought. If it
is elevated but random, you have either a global
mixture problem or a global sensitivity problem. Any
single cylinder thing - valvetrain, injector, ignition -
will show in the individual current misfires.
But a road speed or RPM dependent shake, that's
not about sensitivity. Unless something in the
driveline is so bent and so hard-coupled that it can
push all the way back to the crank. Start with, is it
MPH or RPM?
random. You need to scan it. You need to look at
Misfire Current Cylinder 1 through 8. If one or a few
stand out, you can follow that train of thought. If it
is elevated but random, you have either a global
mixture problem or a global sensitivity problem. Any
single cylinder thing - valvetrain, injector, ignition -
will show in the individual current misfires.
But a road speed or RPM dependent shake, that's
not about sensitivity. Unless something in the
driveline is so bent and so hard-coupled that it can
push all the way back to the crank. Start with, is it
MPH or RPM?
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Joined: Oct 2010
Posts: 2
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My OBD II tells me that my O2 is not ready, Other codes say NA or Not ready. This is because I get the misfire on cylinder #8, I will try everyones suggestions. I only have 27,000 miles on the Bird. I changed the plug, wire and coil. I have stored the car for 11 years and only drove it in summer and nice days.
I think this misfire started after I changed the plugs and wires. I never should have touched them. Would this make that #8 cyl misfire. It does have a great spark. I live in NH so the car will sit from October to April could this possibly be the cause. I also have a Borla exhaust so that my have caused it? Any help I can get I would apprecaite it. I don't feel comfortable Taking the valve cover off, do I have to change the gasket if I take the cover off?
Thanx Jeff
I think this misfire started after I changed the plugs and wires. I never should have touched them. Would this make that #8 cyl misfire. It does have a great spark. I live in NH so the car will sit from October to April could this possibly be the cause. I also have a Borla exhaust so that my have caused it? Any help I can get I would apprecaite it. I don't feel comfortable Taking the valve cover off, do I have to change the gasket if I take the cover off?
Thanx Jeff
My OBD II tells me that my O2 is not ready, Other codes say NA or Not ready. This is because I get the misfire on cylinder #8, I will try everyones suggestions. I only have 27,000 miles on the Bird. I changed the plug, wire and coil. I have stored the car for 11 years and only drove it in summer and nice days.
I think this misfire started after I changed the plugs and wires. I never should have touched them. Would this make that #8 cyl misfire. It does have a great spark. I live in NH so the car will sit from October to April could this possibly be the cause. I also have a Borla exhaust so that my have caused it? Any help I can get I would apprecaite it. I don't feel comfortable Taking the valve cover off, do I have to change the gasket if I take the cover off?
Thanx Jeff
I think this misfire started after I changed the plugs and wires. I never should have touched them. Would this make that #8 cyl misfire. It does have a great spark. I live in NH so the car will sit from October to April could this possibly be the cause. I also have a Borla exhaust so that my have caused it? Any help I can get I would apprecaite it. I don't feel comfortable Taking the valve cover off, do I have to change the gasket if I take the cover off?
Thanx Jeff
I would put another plug in it - I have seen them bad right out of the box - probably due to being dropped at one point or another... especially if it started right after you changed them...
Another thought - if it sits for a long period of time, it may be a sticking injector - run some cleaner through it if it isn't the plug...
The rocker covers use an "O" ring type gasket. You can put it right back if the "O" ring doesn't pop out. If it pops out you won't be able to force it back in so you'll need to install a new one. You can use a mechanics stethoscope to monitor the fuel injectors at KOER. You'll be able to hear the injectors fire everytime they are pulsed by the PCM.
