Spark Plug change miracles
 

Loki started to get a miss under full acceleration and part acceleration above 4k RPM.
I thought it might be plugs but was not sure. 2 weeks later I got a CEL and the code was cylinder 3 & 4 misfire.
Thought this was bad because I was suspecting only one plug was bad and this issue might be something else.
I changed plugs yesterday and all problems fixed with CEL gone and no miss anymore.
Lots of power right up to red line. :)

Mine was a little hesitant last year, I did plugs and got similar results. My wife's 2012 Clubman needed coil packs. I had a plug outright fail on our 2008 Clubman. Definitely seems like something to keep on top of.

Update: unfortunately the CEL code for #3 cylinder is back so I changed coils but the misfire at start up didn't go away.
Still have a miss at higher RPM's and under load but not all the time.
Thinking it is a fuel issue. Investigative work continues. :(

Checked fuel pressure with a snap-on scanning tool and it seems to be in a normal range as far as we could tell. Could not find any specs on what the pressure should be.
Anyone have any ideas where I should go from here without tearing things apart??

change fuel filter..
try injector cleaning treatment..

Already tried fuel injector treatment and seafoam in the fuel tank.
Good idea about the fuel filter. Will try that next, thanks.

Having similar issues with mine that I just bought last Thursday. It's back at the dealer now. Did you sort yours out?

It looks like the fuel filter is not as easy as I was hoping. So did not look at this. I am still having the same issues. Thinking about switching injectors but will have to look at utube to see how easy it is to do. Mechineer84 let me know how you make out at the dealer.

How many miles did you have on the plugs before they needed changed? How much does that number differ from the regular maintenance schedule? Just wondering what MINI's recommendation is and if that is too long to wait.

What was the actual fuel pressure? From doing some reading on here, for the High pressure fuel pump it should be in the 600-800 psi range.

I will answer both previous questions.
First the spark plugs probably have 90,000 kms or (55,000 miles) on them. I just recently bought the car and have no prior service history but I am thinking they were the original plugs.
The old plugs surprisingly did not look that bad. Pull your plugs and have a look at them, lots of good Utube videos on reading spark plugs.

When we checked the fuel pressure it was in the 5000 kpa to 7000 kpa or (750 to 1000 psi) range which is higher than the 600 to 800 psi you have found. When you are driving the graph on the scanning tool has some delay but it seemed to stay in this range so we felt it was in the correct range as it is close to what Ford recommends for its direct injection engines.