Old setup: stock block 91 b18a1, t3/t04e, hondata s200, 440's, Walbro 255

New setup: 94 JDM b18b and all of the above.

Issue: Everything is cool except on startup the car misses and bucks badly, idle is like 100-500, black sute from tailpipe, reeks of gas. Then when the motor is warm, it just snaps out of it and runs perfect (repeated this over several days). I checked the plugs and they were fouled pretty bad. BTW when I transferred them over from the old motor they were perfect (BKR7E).

I'm going to retune asap, but I want to know if this is something tuning related or not. I want the car to be ready for the dyno with no issues.

Could it be something with the cold startup maps being pig-rich (forgive the newbieness ).

Any thoughts?