So I'll start from the beginning last year my aunt passed away (the owner of the car), and my mother inherited it. Everyone in the family already owned a car so the car (2004 E87 120i 120000KM) was left standing for quite some time. I started the car first about 4 months after standing and it started and rode perfectly but then the following day when I tried starting it, there was a 'struggling' noise coming from the engine and it wouldn't start, cuts out after about 5 secs of trying to start. And when it finally starts (after about 4-5 attempts) there is one hell of a violent vibration and fluctuating revs, I then slowly accelerate and at about half throttle it reaches 2500-3000 revs and then slowly cuts out (like it's limiting itself), this happens now and then. After about 4 days of riding i left it and it stood for another 3-4 months and when I started it I got the same story. The most frustrating part is that there are some days like today when even on a cold morning it starts and runs perfectly. I've been riding it everyday this week so far and it seems to be at it's worse in the morning (when it decides not to work) and once it had a starting problem around evening time. The other problem is my airbag and seat-belt light stay on don't know what the problem is with that.
I took this video today to help explain.