check engine on my E320 reads PO700 and PO 715

What is your question?

i have 1998 E320, i need to know what to do something when an driving it moves very well and something it will stock on 20mile per hr, and will not more past that , i will pull over and stop them start the car and it move and drive perfectly fine, but its scarcely because i dont know why and what is wrong with it,what should i do.