The problem that typically causes this is bad solder joints under one and/or both of the touch ics on the motherboard. The intergrated circuits using a BGA (ball grid array) of solder balls and often when the phone is slightly bent or dropped then these connections can become jossled and lose connection which results in spotty or little touch response on the screen.
Read Moreat Wires Computing we offer board level solder repairs for most devices. We have the tools to the repair most technical repairs!
Below is a list of the common repairs we fix:
iPhone 6 Plus Touch IC Replacement
Nexus 5 Power Button Repair
iPhone 5 Series U2 IC Replacement
iPhone 4S No WiFi Fix
Sony Z3V Wifi Repair
Samsung Galaxy S3 Power Button Repair
iPhone 5S 5002 NAND Repair
Samsunng Galaxy S3 Charger Port Repair