Backfire Thru Intake

[1987BlackFox]

Im new to the fox workd and I recenty purchased a 87 gt and as far as I can tell its all original. My problem is when I get in a go to take off it backfires thru the intake and then takes off. If possible can someone point me in the right direction on how to fix this problem. Thanks in advance

 

[mikestang63]

check your timng and for vacuum leaks