Hyundai Repair: 2000 Accent revving high then dropping down for no reason, throttle position sensor, engine control module ecm

Question
I have a 2000 Hyundai Accent 1.5 Ltr. The mystery is that sometimes for no reason it will rev to 3k then drop for no reason to 1k. Even though I don't alter how much I press on the gas. This morning it revved at 5k when I went to start it.  Can you help me. I bought the car in Canada if that matters

Answer
Most likely, the contacts inside your throttle position sensor (TPS) are dirty, causing an erratic signal to be sent to your engine control module (ECM).  If your ECM thinks the throttle is opened, it may not attempt to return the engine to normal idle.  If this is the case, you'll need to replace the TPS.