The reduced engine power light is on and when I press the gas it doesn't go what is wrong n how do I fix it

get a NEW battery....wirebrush the end of the big 1/0 battery cable (not the clamp side...the other side) what attaches to the chassis frame to get a reliable 300 cold cranking amps potential~

your battery is just OLD, as witnessed by the knock-off labels on the top of the battery indicating the date of it's first charge~

batteries will degrade by ten percent per year...a ten year old battery will not take a full charge~

sounds to me like in addition to an OLD battery you have a reduced ground potential by a corroded negative ground connection....they actually WELD themselves with each use creating a layer of corrosion to which the ECU will not be able to rely on varying amperages and varying voltage....so your faulty ECU can be attributed to this corrosion~