Ok, im just going to start from the begining, i bought my iphone 3g from a friend of mine a few months back, i woke up one morning to find a grey dot on my screen so i figured it was a dead pixel and told my self it wasnt the end of the world, so i went on and at the same time my battery life was starting to die faster and faster and after 2 weeks my battery would last 30mins to 2 hours ow and i forgot to mentione that the grey dot during that time became 2 grey lines across the screen, anyway so i decided to order an LCD screen and a replacement BATTERY, so i lived with the problems for 2 more weeks befor i got my parts.

i got the battery first and it was a friday so i figured i would not have my screen before monday so i decided to change the battery and at the time i was a newb and i unscrewed the two screws at the bottom but i tryied prying it open by were the dock connector was just to remember its by pulling on the screen with a sucktion cup but i had already did a little damage around the dock but it looked fine, so anyway i got it open change the battery re-assemble no problems the battery worked fine but i was not getting a signal so i went outside to see if anything would happen and of course nothing so i checked the forums to find out my phone was either screwed and became an expense ipod or the antenna was broken so i order the antenna i got my lcd but waited for the antenna before changing anything, finaly got my antenna [antenna/dock/speaker assembly] and changed my LCD and DOCK still no signal but the screen was realy nice lolll !

I was mad the damm thing was fu***d so i said screw it and put my sim card in my old cell phone and used my iphone for wifi and stuff, and one night at the sports bar i was fideling with my iphone and said ill try my sim card and i got a freaking signal i was so happy [for a bref period] but i was next to a window has soon has i was 2 feet away i would loose the signal and get the famous "NO SERVICE" and still now my iphone will work after a few minutes of being outside but has soon has at school or home "NO SERVICE" gets me mad sometimes, and everything else works great except the signal sucks.

Now ive said all this to ask if anyone can tell me whats wrong or to answer my questions:
1-COULD I NOT BE GETTING A GOOD SIGNAL BECAUSE MY DOCK ASSEMBLY IS A CHEAP INTERNET PART ??
2-COULD IT BE BECAUSE WHEN I TRYED OPENING IT THE FIRST TIME I PRYED THE WRONG AREA AND NOW THE ANTENNA IS NOT TOUCHING THE BACK OF THE PHONE [CAUSE THERE IS A TINY GAP BETWEEN THE ANTENNA AND THE BACK OF THE PHONE] ??

iF ANYONE HAS AN ANSWER IT WOULD BE GREATLY APRECIATED !!

P.S.
Ive tryed all the reset's and firmware and hard start solutions out there

THANK YOU VERY MUCH in ADVANCE !

I'm in the same boat. I even replaced the charging doc / antenna assembly but no joy.
iphone 3g 4.1 OS