I'm not a hundred percent sure what's going on at times with my Mini, but when the engine hasn't been driven for a while, say next morning, and not all of the time, I get a loss of power at times. Like it just lost boost while the RPM's are climbing. I can pump the gas and it sometimes stops the power loss. Then after the engine is fully warmed up after 5-10 miles, it drives always perfect. I was in the dealer about 2 months ago, just before warranty was out and they said there was a misfire code in the history and said the valves were dirty. They cleaned them under warranty, scraped them with a pick, medi a blasted etc. Now it's starting up again. I'm not sure if it's something more with the tune, or the valves need a better cleaning, or need of oil in the engine. Seem to go through 1/2 qt a month on hard back country road driving. Dealer ship gave me a service later stating that was normal for minis. It said they can burn up to 1 qt per 750 miles and that is normal depending on conditions. The fuel is 95% of the time shell 93, and I put in Sea foam about every other month in the fuel tank only.

 

Seafoam in gas tank doesn't do anything. For the bogging down, I'm not sure. It could be something going bad with the fuel sitting for a long time or some of the other fluids