Sprinkler System Low Pressure
The size and configuration of the entire piping system that supplies your irrigation setup, from point of entry to your property (usually the water meter) all the way to each sprinkler head, along with pressure, determines how much water is available. Pressure is just one piece of the puzzle.
If there is a regulator on your system it would typically be found on the main water supply pipe, between the main municipal supply/meter and your home (upstream of everything, basically). You should understand that regulators are installed for a reason; removing, bypassing, or adjusting it could cause complications up to and including failure of system components (i.e. flood). Normally, if high delivery pressure necessitates installation of a regulator, then all your neighbors would have one as well. It would be prudent to do some asking around. Regulators usually look something like this:

In the end, the cause of your problem is usually due to undersized piping. the fact that your neighbor used a different irrigation installer and seems to have no issues points to that as well. You would be surprised at how much more water flows through a 1&quot; pipe compared to a 3/4&quot; pipe:

By taking pressure measurements (both static and with water flowing) and noting pipe sizes and configuration, an educated layperson (and certainly a landscaping professional) could diagnose the issue fairly quickly.