Possibly, but probably not. The Trottle body balance is about air, not fuel. Try balancing the throttle bodies and looking for blockages in the air flow at the radiator inlet.
Fuel
Spark
Air
These are the three things required for the engine to run. Typically fuel issue would be worse at higher rpm where demand is greater.
Spark - could be shorting at the coils. You changed the spark plugs. Did you notice any corrosion on the coils or tubes running down into the spark plug wells? A bad coil or shorting could cause this. Spark issues can sometimes improve at higher rpm and be poor at low rpm. The opposite is also true, runs ok at low rpm, but under strong demand misses and runs poorly.
Fuel - Dirty fuel filter sock in the tank could be causing issues, but again I suspect this would only be worse at higher rpms.
Air - Vacuum leak/crimped lines? Unbalanced throttle bodies, partially blocked air flow to the intake or radiator.
I hope this gives you some ideas and places to look. Good luck and let us know when you find the problem and how you fixed it.