1997 C1500 code p1345

hello all, i am in need of desperate help. my truck has been down for over 5 months now and i cant figure it out. it started out as cylinder 1 low compression, so i figured while i was there id do a partial rebuild. unbeknownst to me, timing on a 97 is horrible work. after a bunch of research, i found that the only way to fix the timing on a 97 is with a scanner. tried it and nothing. i’ve tried everything i can think of but nothing works. the only code i have is p1345 and i can’t figure it out. any insight or help would be greatly appreciated!!