I have a 94 accord with a h22 euro r swap. Had the swap done a yr ago car ran fine up until recently I changed my spark plugs n spark play wires both ngk. Last week I started the car n it was misfiring on startup but once it warmed up it ran regular no misfiring. What could be causing the misfiring on startup

 

Sounds like a plug is not firing. Check to make sure the plugs did not come lose and check that the plug wires are secure. From there make sure the distributor wires are properly secured.

 

I'll second this. I've had that happen a couple times with AL heads. Usually ~week after the replacement of plugs. Make sure they are the correct tightness(don't torque the begesus out of them) and the car should be back to normal.

 

Just make sure that there's no leak in the plug wires and do make sure that the plugs aren't loose like mentioned above, never know.