Write a formula for your definition of a gap up. So for example, if it means the open is above the previous close.

O > C1

If it means the open is above the previous high.

O > H1

If it means the low is above the previous high.

L > H1

Or it might mean something like the open is at least 1% above the previous close.

O >= 1.01 * C1

Use the desired formula as a Custom PCF % True Indicator. Set the Average Type to Simple and the Period to the number of bars you want to check.

You can click on the Custom PCF % True indicator to use it as a WatchList Column and sort or Create Condition (or Create Scan Condition) to create a condition based on the percentage of the time each symbol meets the requirements of the desired formula.

How do I make a custom pcf % true indicator? Thank you for your help.

It is just a regular indicator called "Custom PCF % True Indicator", so you would add it the same way you would add something like stochastics or a moving average.