I swapped an 87 FI 13B into another car and finally got it running - it fires right up and appears to run pretty well - will tach up pretty decently when cold, but after it's warm, when you hit the gas it sputters and pops and after a couple seconds it will eventually rev up, but something is definitely wrong. It could be my wiring??? any suggestions what to check or any diagnosis??? please help - i'm stuck