My big mistake when I started writing was forcing the reader to jump into my brain. I had nothing but action, no breaks, not even room for imagery. It read like the synopsis of a book. Pacing is not just the action, but also dialogue, scene placement, and the use of point of view changes. You need to examine each scene and its placement.
Most people have little trouble with the pacing.
Check out Count Zero, by William Gibson, or Snow Crash, by Neil Stephenson. Both of these have different ways to keep the reader reading and not sleeping or pissed off. Don't pace too much. Keep the action scenes moving. If you are not in the right mood, with your head in gear, and want to write, you will not be able to write.