cylinder 2 misfire p0302

[acko]

need help with a misfire cylinder 2, about two week ago got a service engine soon, scanned it with obd2 got p0302. changed all the spark plugs and a coil 2. the car was fine for two days and then again the engine light came back. now i changed the cylinder 2 fuel injector and same situation is happening. when am driving the car around 40 mph "higher gear, lower speed" the vehicle start to "jerk" only when am having my foot on the gas. don't know what else it could be, please assist ohh yea the car is,,,

2004, bmw x3, 3.0l, winter package.

also, what is the firing order..

thank you..
sifet

[easonliu]

Is your engine stumbling or hesitating?
check all wiring and connectors that lead to the cylinders, and spark plugs, spark plug wires, distributor cap, and rotor (if necessary, have a replacement),Otherwise, check the coil packs..i

[ZetaTre]

Originally Posted by easonliu

Is your engine stumbling or hesitating?
check all wiring and connectors that lead to the cylinders, and spark plugs, spark plug wires, distributor cap, and rotor (if necessary, have a replacement),Otherwise, check the coil packs..i

REALLY!!!!! Distributor cap and rotor... Have you ever even open the hood of the car?

Anyway...

These cars are known for vacuum leaks and although normally the symptoms are spread across multiple cylinders, I wouldn't rule it out.

1) The branch on the intake manifold that goes to the idle control valve cracks.

2) The crankcase vent valve and plumbing around it fails: not really a definitive way to test it, but a known items that crap out: you would have to replace the whole thing...

I hope this helps.

PS: firing order should be 1-5-3-6-2-4 (with 1 being the closer to the bumper)