2012 Clubman S with intermittent 1/2 power indicator
 

Ok, so I just got this Clubman with just over 50K on it. Runs great, but had to travel from VA to PA (250mi) for family issues. I plan on replacing fuel filter and give it an oil change, just haven't had the chance just yet (when I get home). Got to about 60 miles of my destination after hours of Interstate speeds and the 1/2 power indicator comes on. I pull off in a rest area for a few minutes to research quickly and then decide I can make the rest of the way on side roads to minimize speeds. Only stopped for a few minutes... as soon as I started rolling, it clears and I have full power. I don't have any other indications, no sluggishness or hesitation. I only put a single take of top tier premium prior to this trip, averaged 22mpg (city), but I'm not too sure of the accuracy since I don't have any other measurements to compare. Tank of top tier midgrage (still 91) got me almost 34mpg. The light, driving for a couple of hours in the city did come back on yesterday, but as soon as I stopped for a minute or two, it cleared.

So, I'm asking for opinions and recommendations. I don't have a code reader with me so I don't know right now what, if any, code is being thrown. Now reading, this indicator could be thrown for things like a hiccup in the fuel system or I've read it could be caused by a faulty thermostat. Both are relatively common failures from what I've read and heard. My coworker I've been talking to thinks it might be the high pressure fuel pump, but I'm not seeing any other symptoms. I'm leaning on the thermostat seeing it looks like my mpg is considerably better with the engine hot (possible indication thermo stuck open). My normal commute to work is only 15-20 minutes, so the car dosen't have a chance to get hot.

I'm looking for advice since I'll have to do all the work myself. So I'd like to get the problem fixed and worry about "preventative" maintenance (like replacing the HP fuel pump later if it's working fine now).

Thoughts? Thanks in advance!

I know I just asked the question, but I continued symptom analysis based on my observations and what could cause that indicator. I found that it could be caused by an air intake leak or a bad O2 sensor, causing the fuel to air ratio computation to be off. Long story short, looked at my airbox and saw that the intake side of the box was disconnected, so the filter wasn't pulling air from outside of the car. At high speeds, car seemed fine. Thinking about it, I got the light if I had slowed down (at a rest area) for a bit or drove slow for a while. Don't know yet if this fixes my issue, but I think it could be part of the issue. Air filter is dirty but not overly dirty. New one is on its way anyway.

Also, realized last week that the three grommets holding the airbox are missing (well, found part of one), so I'm not sure if the intake just jostled itself off or if it wasn't reinstalled correctly after maintenance. I'm thinking the latter since it still locked into place correctly. My question, could this have caused my low MPG on my first tank after buying it? Guess we'll find out, drive to Virginia tomorrow.

Although I'm stressing being so far away, hoping this simple fix is all I needed to do.

So did this solve your issue or did it persist?

Did you get this resolved? Im curious as to what the issue was?