Hello, I'm new to this and would really appreciate any help!
I brought a Mini Cooper r53 s 2003 about a month ago, it came with the engine management on and abs, asc, and tyre pressure light on, I fixed it with a new sensor and reset the code on the engine management, but it came back on saying 'bank 1 system running too lean'
The car when when warm, pull up at the lights, it will either drop to about 700 rpm then pick itself up to 2200 for a couple seconds then drops.
When pulling off the power seems to drop and almost bog out before it picks up unles you give it some *****, the car does get very hot, but the temp gauge reads fine, the coolant is clear when it goes in, and the second time now I have flushed it and it's come out orange or rusty, any advice or hep would be great as I don't have a clue what to do and Bmw is EXPENSIVE to say the least haha thankyou

 

Sounds like you have 2 or 3 separate issues...
A vacume leak or boost leak is probable... Giving you an idle issue/lean code...hear and hissing or sucking sounds?
As for "running hot", first off....I would suggest using a coolant...usually not clear in most of the world...the iron block tends to rust with plain water...not sure where you are but in north america BMW coolant is tinted blue, others yellow, orange, or bright green....
And once the coolant is filled...it need to be bleed, (look it up)or it will usually overheat... Make sure the overflow cap is good too...

 

I have been hearing a sucking recently but I think that's because I havent changed the boots on my new intercooler, but the problem was there even before that aswell, as for the coolant I'm in England I joined for advice because I have spent near 2000 on parts and it's still not sorted, I will change it to coolant instead of water, but what do I do about the rust already in there? Because everytime I flush it it's staying orange, and I did bleed it, but I will again just to make sure, thankyou

 

You cannot fix an item if others are present...your "leaking boots" might be causing or masking other issues....fix the boots...then you can look deeper...lots of tricks, anything from idling with an unlit propane touch aimed at fitting , listen for idle changes to soapy water or a "smoke" test can be done...
Go to the local auto parts store...tell them you have a rusty block...there are various treatments to stop and seal the corrosion... I would flush the heater core...it tends to collect fragments, and plug up...giving you u another issue...and I don't even want to think what the rust has done to the water pump seals....
Getting a neglected car can be a money pit...but you might get lucky...
But you are the detective...and unless you have the $$$ to pay a pro...I hope you get good at it fast!

 

2000 in parts.huh...
Might have been cheaper to spend 200 for a pro...then another 200 in parts...
Sometimes learning is expensive...

 

I will change the boots asap and I'm gonna take the rad and pipes and ecpension tank off and flush maybe get newboiled but what I've just noticed is if I let it ride the clutch it sits at 2000 rpm as well and then when I put my foot down it drops then picks up