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When the code P0306 is set in the Power Train Computer, it means that the Misfire Monitor
has detected more than a 2% variance in rpm between the firing of any 2 or more cylinders in the firing order. The Misfire Monitor constantly checks the rotational speed of the Crankshaft by counting the pulses of the Crankshaft Sensor. The Monitor wants to see a smooth increase or decrease in engine rpm. If there are jerky and sudden changes in the speed output of the Crankshaft Sensor the Misfire Monitor begins to count the rpm increase (or lack thereof) contributed by each cylinder and if it varies beyond 2%, the Monitor will set a P0306 code and illuminate the Check Engine Light. If there is more than a 10% variance, the Check Engine Light will blink or pulse in a steady manner to warn the vehicle operator that a Catalytic Converter damaging misfire is occurring.
Why can't anyone post wtf they found wrong with the cylinder misfire? Same problem here, cyl #6 misfire, swapped injectors, coil packs, spark plugs with opposite bank with no change. Remove ECU and found some white corrosion on a few terminals on a plug on the back side. The result of water leaking from somewhere above it. (Ford TSB 08-26-7) I assume that the ECU is bad. May post this in a new post.
I'm stuck... Along with the "cylinder 6 misfire" issue, I also have a "Bank 2 Air/Fuel Ratio Imbalance message" as well as a "Misfire Detected on Startup First 1000 Revolutions" - My guess is these messages are all related. I replaced the spark plugs and it seemed to fix the problem for a while. I also switched the coil #6 with coil #5 and, to my chagrin, I have the same issue... I have a Flowmaster Outlaw catback exhaust and a Borla cold air intake. I'm not aware if other mods have been done to the vehicle since I purchased the car used from a dealer in Halifax in May 2020. This issue started later in the fall of last year.
I'm stuck... Along with the "cylinder 6 misfire" issue, I also have a "Bank 2 Air/Fuel Ratio Imbalance message" as well as a "Misfire Detected on Startup First 1000 Revolutions" - My guess is these messages are all related. I replaced the spark plugs and it seemed to fix the problem for a while. I also switched the coil #6 with coil #5 and, to my chagrin, I have the same issue... I have a Flowmaster Outlaw catback exhaust and a Borla cold air intake. I'm not aware if other mods have been done to the vehicle since I purchased the car used from a dealer in Halifax in May 2020. This issue started later in the fall of last year.
It sounds to me like you have a fuel injector issue. Perhaps give that a try?
On another note, I've been having the same issue as listed by OP. I'm going to dive into it this week and see what I can find. I just replaced the spark plugs so I think that's going to be the first culprit. If I find nothing wrong with the plug, I'm going to swap coils. If that doesn't fix anything, I'll swap injectors. I should probably also check my oil. Maybe low oil pressure has something to do with it with the variable valves?
Well, after digging into the issue, here's what I have determined could be some potential things for other members to look into, as well as a description of what happened to my car.
Potential culprits:
* Spark plugs (visually inspect)
* Fuel injectors (visually inspect spark plugs for signs of rich or lean condition)
* Coils (test with a multimeter and or test light)
* Camshaft position sensor (test with an oscilloscope or multimeter)
* Crankshaft position sensor (test with an oscilloscope or multimeter)
* Intake manifold gasket (test with starting fluid around the base of the intake manifold)
I was getting lean pops below ~15% throttle. I was getting the P0306 code (cylinder 6 misfire). My spark plug was completely burnt from an extreme lean condition (photo included below). Therefore, I determined that my cylinder #6 injector had gone bad. To test this, I started the engine, and while it was idling, I disconnected the electrical connector on the #6 fuel injector, and the engine idled relatively the same. I plugged #6 back in, and made my way around the engine, unplugging each injector, noting a large difference in the way it idled, and plugging the injector back in before moving on to the next.
Well, after digging into the issue, here's what I have determined could be some potential things for other members to look into, as well as a description of what happened to my car.
Potential culprits:
* Spark plugs (visually inspect)
* Fuel injectors (visually inspect spark plugs for signs of rich or lean condition)
* Coils (test with a multimeter and or test light)
* Camshaft position sensor (test with an oscilloscope or multimeter)
* Crankshaft position sensor (test with an oscilloscope or multimeter)
* Intake manifold gasket (test with starting fluid around the base of the intake manifold)
I was getting lean pops below ~15% throttle. I was getting the P0306 code (cylinder 6 misfire). My spark plug was completely burnt from an extreme lean condition (photo included below). Therefore, I determined that my cylinder #6 injector had gone bad. To test this, I started the engine, and while it was idling, I disconnected the electrical connector on the #6 fuel injector, and the engine idled relatively the same. I plugged #6 back in, and made my way around the engine, unplugging each injector, noting a large difference in the way it idled, and plugging the injector back in before moving on to the next.
where you also by chance running a code for loss of compression mine is doing the same but with a loss of compress that’s randomly jumping cylinders during diagnostic
where you also by chance running a code for loss of compression mine is doing the same but with a loss of compress that’s randomly jumping cylinders during diagnostic
it sounds to me like a crankshaft position sensor being dirty or faulty. The way your engine checks for a loss of compression is by measuring speed increase of the crankshaft on each power stroke. If your crankshaft position sensor is going bad, it will not only cause a misfire (because the engine is sparking at the wrong time) but could also trigger a loss of compression code. If I remember right, it’s like $10-20 for a new sensor off of Rock Auto, and it’s not an extremely strenuous task. I’d recommend starting there.
01-18-2010, 06:10 PM
