Hyundai Elantra Engine Idle Erratic

This Vehicle Excelerates And Decelerates In The Park (idle) Position. What Is The Problem? Thanks.

While Driving, The Rpm Guage Will Go Up And Down But It Doesn't Cause The Car To Function Differently.

01 Hyundai Elantra.replaced Bad Alternator,now It Surges At Idle Until Computer Sets,then It Revs To 4000 Rpm. Code P0121,replaced Tps,still...

My Daughter's 2001 Elantra Has Been Throwing A 0303 Ods Code For A Month Now. Coil, Plugs And Plug Wires Have All Been Replaced. Now Car...

As A Note I'm Not Actually Sure On The Engine Size. Hi, And Thank You To Anyone Who Reads This And Even Considers Helping As It Has Been...