i have a problem with my 91 gt. once in a while it will just stall out at a low speed or at idle, but most of time will fire right back up. it has a carbed 347 stroker with msd 6al and brand new msd pro billet dist. it was fine up til i put another c-4 in and as soon as i got it back together it started giving me this problem. all the grounds are still same for the msd box, pretty much nothing was changed. any help is appreciated