Ford Repair: Surge, sticker shock, trouble code

Question
2000 Merc Mountaineer 4.0 Auto.  diagnostic tune up done, plugs, wires, fuel filter...all needed done....still have a surge issue.  Speed doesn't matter, idle is fine, no missing.  Direction to go?

Answer
Test the fuel pressure to rule out a fuel pump going down.If the pressure is fine have a diagnostic run with a genesis scanner.A sensor could be going down without tripping a trouble code.Those scanners are quite expensive,so expect sticker shock issues from the bill.