Just did a quaife LSD and OSGiken clutch/FW combo done and had a p302 cylinder 2 missfire code got home and checked and cleaned cylinder #2 wire contacts and all is good now. Wierd thing was it would only happen when boost reached 12-13psi 4-5 gear. If it continues I will get new wires and plugs all around. And yes the new bits are sweet!

 

I am resurrecting this thread because I too am having a p0302 code and cannot find the cause..
compression test came back good, I don't remember numbers but all were above 150 and between 150-165 so I imagine the valve are fine. And they were all high and equal enough I didn't even remember to keep the scratch paper I wrote down on.
I have since replaced coilpack, wires, fuelinjectors , front 02 sensor and cleaned both map sensors. Fuelpump and fuel filter are new too.
I have knowticed that the code ONLY pops on when my fueltank level is below 1/4 tank.
I only seemed to get this issue abit after swapping to a facslift ecu with a GP tune. Could i have been sold a bad ecu and this is the cause for the random p0302 code ??
swapping plugs and or plug wires as well as injectors does nothing , the car runs absolutely perfect. No stumbles or missfires or any powerloss what so ever. I will just be driving and the code will just randomly come on and illuminate the cel...

 

Did tou peform a leakdown test on the cylinder. I had same issue. Turned out to be a small warp between cylinder 1 an 2. Had it resurfaced an no further issues.

 

Odd... chemical b12 through the intake and some in the gas and then cleaned and reinstalled the sparkplugs and immediately took the car for a hard drive and went and ran with a buddies r53 I've been fixing up for him ( our minis were EXACTLY even off the line upto 100+)
but THE CEL IS GONE !!!!!!
I drove plenty long for the cel to come back but it hasn't and actually the car seems to idle abit lower but smoother now. Befor i could idle the car for 2min and immediately upon restart the cel would be on for the p0302.. my ONLY guess is somehow It's valve was dirty or sticky and the chemical b12 and hard drive cleaned out what ever was causing it.