Rep Power: 0

I have a 2013 honda civic lx coupe. Sometimes, not always, when I take off from a stop slowly the car sputters. If I give it a little more gas it stops. I bought the car about 5 months ago. When I bought it I had to replace the catalytic converter. When the check engine light came on for that the guy at o reilys said that all I needed was a $35 bottle of something in the gas. Well that was not the solution. After we installed the cat I replaced the spark plugs and gave it fuel injector cleaner. When the car is cold it doesn't do it so much. Please help me out.

 
Rep Power: 222

What brand of plugs did you put in? Gapped properly?
got a scanner?

 
Rep Power: 224

Possibilities:
-Needs new spark plugs.
-Faulty ignition coil pack.
-Dirty or faulty fuel injector.
-Low fuel pressure.
-Out of spec valve lash.
-Etc, etc....

To me, it sounds like a fuel issue. Extra fuel is added when the engine is cold.