I got Duralast and Anchor both were defective and the bolt holes don't line up, save your money and get poly or just get OEM so you can save yourself the hastle
If the problem was corrected them the light should go out, or clear it, if it comes back then there's your issue. it sounds like your 1st/2nd clutch in your trans is done, look at rebuild kits, but is your D4 light stay on when your KOEO
Flashing MIL(check engine) is damage to catalytic converter, usually like everyone is saying a misfire, as for your low idle it could also be something with your IAC