I have a 2010 Clubman S with 80,000 miles. Recently it has been hard to start only in morning the first time. It will run rough and not accelerate. I have to give it about half throttle while I crank the engine and then keep it about 2000 rpm for a few seconds. Then, it starts fine and runs fine the rest of the day. Gas mileage is great and performance doesn't seem to be suffering I have a Scan Gauge and have the following codes showing- P0300,P0001,P0302, P0203,P0103, P0403, U3F00,B2A00,B2AAA. Anyone have any ideas?

 

High pressure fuel pump is a good bet.

 

HPFP is a good place to start.

https://www.northamericanmotoring.co...r-r56-jcw.html

 

Any other way to confirm? I hate too spend $1000 and then find out that is not the problem.

 

Buy it on ebay for much less than that. The p0300 codes are misfire codes. Check pressure amd spark, if both are good, there goes your pump.
Also check car-part.com
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For what it's worth, I had the same hard starting issue at about 120,000 miles and replaced the HPFP (before the price jump) and my problems went away. I didn't have any codes, though.