injector fuse keeps blowing out

[wtf-u-say]

i have a 2000 daewoo legansa 4 cyl, and the injector fuse just recently started blowing out. now it doesn't blow out on short trips. it seems when i drive far this problem starts. I have read a couple of articles and it points out that the camshaft position sensor may be the problem. i would greatly appreciate it if someone could help me or tell me how accurate this is. THANK YOU.....