Iphone 4 charges slow/no icon/changed port/erased and restored/motherboard issue?

Believe this occurred after using a cheap dollar store car charger(I know...dumb). Anyhow, phone charges extremely slow but doesn't show the charging icon. Does not connect to PC/Itunes. So far have completely erased the phone and restored, replaced the charging port, changed battery, nothing has worked yet. Is it a motherboard issue? Can anyone point me in the right direction. Thank you

via Welcome to gsm-tips http://forum.gsmhosting.com/vbb/f631/iphone-4-charges-slow-no-icon-changed-port-erased-restored-motherboard-issue-1749544/