HELP!!! Car runs then Dies

[goldwidebodymr2]

I hope 1 of u can help me, my car starts and idles smooth, then when i throttle the car it stalls, drives fine no missfiring, just have to keep the revs up, as soon as the revs drop it stalls, happend after the battery went flat had not driven the car in about 3 weeks.
Also i jump started the car i hope i havn't fried the ecu??
also the engine light flashes and as if its pinging on idle, the air fuel meter says its lean on idle, is this normal????....

What can it be?

Its a 1993 MR2 Japanese Import

Please help me