BIG PROBLEM need some help

[SachaB6]

Hi, so last week i went untronicstage 2, with a atp test pipe ,380cc injectors, samco hoses, forge splitter, knn drop in, and denso cold plugs.
So everything was fine for a week. Then i got a check engine, didnt think much of it, i stil drovbe it for a couple days. Now its really cold here in Montreal, Around -4 lol, and everytime I start my car when its cold, it doesnt rev to 1.2k rpm anymore it stays at 0.8, and if I dont wait like 15 minutes, If i start putting gas ,the car stalls...... It does this everyday now and im kinda worried.... what could this be??? test pipe?? battery?? alternator???
thanks, Also when my car is warm, it doesnt do this anymore.

[old guy]

The low idle is normal when the temperature drops much below freezing.Clicky click Also you may need to go up one heat range with your plugs for the winter months.

[Molotov]

probably sparks, my car has been stalling on cold starts around and it's only ~25 F. Stupid performance spark plugs... >:( putting some BKR6E's in soon

[Sp3C14L 3D]

definatley isnt the testpipe, has to do something with the ignition or spark plugs