2001 MG ZR engine management light

Hi,
I was in the middle of my journey home and as I was slowing down in traffic, I lost power. I pulled over to the side and revved my engine and she seemed fine. Just kept my revs higher when pulling off and as soon as I shifted to second gear, everything was normal. Had no further problems. Popped into a shop and it really pelted down with rain. Had bought some redex as I thought I as I had run her low on petrol a couple of times that may have caused the problem. When I started her up her engine management light came back on. She drove normally.

I have driven her today and the light is still on but she is driving well.

Bit of background:

I have a dirty ABS sensor and I have had my front brakes changed reently.The lights are still comong on especially when it is hot weather.

I have also had all my leads and coils changed in the last 6 months.

She failed her MOT (November 2010) as her emissions were reading high. This turned out to be an ECU issue and was resolved. Her management light has been off since beginning of November.

I have also just gone past 105 000miles on the clock.

Thanks