Random time interval between seconds

I’ve been using a script through Greasemonkey to perform an automated process on Instagram but because the timer is exact I think it’s easy for Instagram to block it. This is the script I’m using

// Just checking if page loaded an
// Find this face it where program jump to start <(O.O)>
window.addEventListener('DOMContentLoaded', function() {
 console.log('window - DOMContentLoaded - bubble'); // 3rd
function simulateCliks(el, evntType){
 if (el.fireEvent) {
   el.fireEvent('on' + evntType);
 } else {
   var evObj = document.createEvent('Events');
   evObj.initEvent(evntType, true, false);
   el.dispatchEvent(evObj);
 }
 likes++;
}
//  <span class="glyphsSpriteHeart__filled__24__red_5 Szr5J">Unlike</span>
//  <span class="glyphsSpriteHeart__outline__24__grey_9 Szr5J">Like</span>
var greyHearts = [];   //	Array of unliked things
var likeButton = [];   //	Array of buttons
var scrooltobottom =0;
var fixedScrool = 1600; //	scrool for 600 px
var timerInt = 7000; //	7 sec

// <(O.O)> starting here with timer
 setInterval(function(){
   // Selecting all not "Liked Hearts"
   // So we will click "Like" and "Next"
   // Each time then pass simulateCliks function
   greyHearts = document.getElementsByClassName("glyphsSpriteHeart__outline__24__grey_9");
   simulateCliks(greyHearts[0].parentElement, 'click', likes);
   	// Finding right buttons
   window.scrollTo(0,scrooltobottom);
   scrooltobottom=scrooltobottom+fixedScrool;
   console.log(likes+"-- likes for this session");
   // Ctrl+Shift+I
   // Find Console and see stats
   // Thats all folks
 }, timerInt);
});

What I want to do is randomise the time where it says

var timerInt = 7000; //	7 sec

I want to randomise it to perform the action between 1 and 4 seconds instead of an exact number of seconds Is this possible? I don’t know anything about writing JavaScript