93 lt1 runs great after 15 minutes of driving but chugs back fires out of intake when cold, idles fine just will not run 1500-2200 range cold.No codes replaced opti,plugs,wires,o2,map,prom,ecm,coil and fuel pump all injectors are with in limits k&n intake edlebrock headers.Again the car is a strong 13.80's runner just will not run cold start up any help thanks.

 

Possibly a problem with the coolant temp sensor not telling the ECM the correct engine temperature. If the ECM doesn't know how cold the engine is, it can't apply the correct cold start A/F enrichment.