I'm using glaxy grand (I9083). I was facing this touch problem. For example, if i touch and hold letter 'e' on my keyboard to enter number 3, it will type bunch of letter e's (eeeeee). First I thought it was some software problem(touch driver). But today I found out that if I remove the back cover and use the phone, problem goes away. Weird right?. Anyone know how to fix this?
Might be because of static charge accumulated during charging. Use the stock charger if currently not using also there are many tips to remove that static charge off your screen. Try those and tell us.
Ivcode ,this maybe a solution for your problem.
First of all ,try to upgrade your android.
Second,go to settings>my device>display.
There must be an option at bottom named 'Increase touch sensitivity'.
Tick it and you are done!
If it helped then please reply, if not then let me know what happened.