I've got a 2000 USDM Integra TypeR(stock). I red-lined 3rd into 2nd(assisted by a few distractions)

I've replaced the timing belt,distibutor cap,rotor button,NGKplugs&wires&pcv valve. Also im about to replace the valve cover gasket & fuel filter.
I'm recieving codes; (PO302) Cyl. 2 Misfire, (P0304) Cyl. 4 Misfire, (P0300) Random/Multiple Cyl. Misfire Detected, (P1399) Manfacurer Control Ignition System Or Misfire.
With the stuff i've already done, i've got alot of improvement.The engine seems to be running strong only that the valves are louder than normal.If i drive it, as soon as I let off the gas it dies,without driving it; in idle it stays running but at around (4-500) RPM.
Any help would be very much appriciated.