Yes. In flow injection analysis, you place an union instead of the column (or a tubing that directly connects the HPLC injector to the MS) and make injections of a certain volume of standard solution (typically the injection volume that you are going to use in LC-MS) at regular intervals while modifying parameters. This provides a gain of time compared to LC-M injections. This is different from MS infusion where you would infuse a solution at a low flow rate in the MS using a syringe pump.
Usually, people first start with MS infusion to optimize compound-dependent parameters (e.g. collision energy, fragmentor), then move to flow injection analysis to optimize source parameters (desolvation temperature and flow, ESI voltage etc.).