Miss fire

What is your question?

Have hard cold start replace the fuel injector spark plugs and wires too help fix the issue friend did replace the mass flow sensor now bank one is running rich and bank five is miss firing . Now when turn the key take longer too start

What makes this problem better or worse?

Cold start is worst when cold

How long has your 2011 Chevrolet Silverado 1500 had this problem?

Few weeks