2004 Chevy Impala High Idle Speed Car accelerates on own

I have been having trouble for the last 1 1/2 years with an intermittent problem when starting my car I will get a high idle (sounds like a jet engine) sometimes if I push the accelerator as I am turning the car off it will help me have a normal idle when I resart the car. The car has also been know to idle high when driving it I can go as high a 40mph without putting my foot on the accelerator at all. If I am lucky enough to get a code (haven't had one in over a year now) it will show TPS which has been relaced 3 times already. Anyone have any ideas before this car gets me or someone else hurt in an accident?