2005 Sport Trac surges and bogs down

[lwrat]

2005 Ford Explorer Sport Trac surges between 1000 to 500 RPM's while in park. While driving truck will lose power momentarily until accelerator is applied then surges with power. When vehicle
comes to full stop vehicle bogs down again then surges again when accelerator is applied again.

 

[1Aauto]

It could be a bad EGR valve or possibly a bad IAC. You may want to check those two components to see what condition they are in.