New Guy Question
 

Just started getting in to learning about vehicle engines and such so I'm a beginner. Aside from oil changes or an air filter change I've never seriously worked on my 1997 F-150 so I mean it when I say I'm a beginner.
When I am going down the road and I turn my flashers on my engine revs itself up without me pushing any harder on the accelerator and then revs up again when I turn them off. This doesn't happen every single time I turn them on though. Thanks for any feedback.