'03 base model, issue with engine and acceleration...ECU?
 

I own a 2003 MINI Cooper, and today I drove to a cafe after work. When I went to leave, my engine wouldn't start. Everything else came on and I heard the clicking, but the engine wouldn't turn over. I tried a few more times. Still nothing. When I waited for a minute and tried again, it finally started. Pulled out of the lot onto a pretty busy main road and could not accelerate. After I floored the gas pedal for a few seconds the car finally sprang to life.

Is this an ECU issue? Is it something I could check myself and fix?