Do you have a page on your website that is taking longer to load then others?
Your problem could be the image size.
You don't have to purchase any expensive software to reduce your images size. Instead you can do it all for free. It will take some work, but it's well worth it.
As a general rule of thumb I like to keep my image sizes below 50 KB.
Only use .jpg for your images. Do not use .gif or .png for images. Both .gif and .png will make your image sizes to big.
The two tools that I used in this video are:
Try this on your ranking pages on Google. It will make the user experience better and your rankings will increase as a result.
Let me know if you have any questions.