analog pins

Hello All
Im having a issue with a Arduino Mega. 2560... if i run this sketch
/*
AnalogReadSerial
Reads an analog input on pin 0, prints the result to the serial monitor.
Attach the center pin of a potentiometer to pin A0, and the outside pins to +5V and ground.

This example code is in the public domain.
*/

// the setup routine runs once when you press reset:
void setup() {
// initialize serial communication at 9600 bits per second:
Serial.begin(9600);
}

// the loop routine runs over and over again forever:
void loop() {
// read the input on analog pin 0:
int sensorValue = analogRead(A14);
// print out the value you read:
Serial.println(sensorValue);
delay(1); // delay in between reads for stability
}

I get mostly High Numbers and it skips most mid range and low Numbers... I guess you could say the output responds very fast at the low end of the pot then is very slow on the upper end
287

288

290

294

303

317

338

353

410

456

591

785

964

972

985

990
this is a sample of what Im talking about..
other analog pins seem fine. So why is this pin doing it?
Any help would be great

Could be you have an audio taper pot, vs a linear taper pot.

I've used the same pot for other pins and it works fine. The reason this is a issue for me is I use this board for a 3d printer and this pin reads the temp probe. And well I get no reading from it. So I've checked the ramps board and all seems fine so I started troubleshooting the arduino and thought that using a pot would be the best way to test.

Any one else have any ideas?