[Myfathersson]

Sounds like a fuel issue to me, but I'd still check the plugs and make sure they're clean and properly gapped. That's easy and quick.

Did you replace the fuel filter/separator when you flushed? I presume yes. Filter, pump and fuel supply lines would be my first stops. Also check the tank vent line to make sure it's free and clear.

After all that I'd measure the resistance on the plug wires and make sure you're not getting a cold spark.