Hello, I have recently replaced a ton of things I’m a mini. I live 500 miles from the nearest dealership. Things I’ve replaced mass airflow sensor fuel filter turbo vacuum lines water pump alternator water pump pipe or cooling houses, thermostat housing. No I’m having an issue when I start my car it’ll start idling rough and it will stall. It will bounce between one grand and too low if I step on my gas and let it go to three RPM’s after a while I won’t have the idol issue but is soon as I turn off my card comes back. If I unplug my mass airflow sensor even though it’s new and I bought a good one it idols just fine.I thought I was having a fuel issue so I changed my fuel filter it was black, I also drain the gas tank just to make sure my fuel wasn’t bad. It fix the problem for about six hours. 
I have brand new spark plugs in there, but from what I’ve been looking online it sounds like I’m either having one or two problems maybe it could be my ignition coil’s, or it could be my high-capacity fuel pump can somebody please help me there’s not a competent mechanic near where I live the nearest BMW dealership which doesn’t work on minis is quite some distance from me and then the mini dealership is really far away can someone please help