Erratic Idle
 

Lately I've noticed that when I come to a stop light and put it in neutral or in park, I get an erratic idle. It sounds as if I'm reving and coming off the gas, reving and off the gas, and doesn't stop. Anyone ever experience this?

This just started to happen after I put in that fuel injector cleaner(never again). Could it be one of my injectors messing up? I thought it would stop after all that cleaner went through but I'm almost at the end of the tank now.

vacum leak, iac, and check your harness for any cuts etc.