Toyota Repair: PO402, tool checks, scantool

Question
99 Tacoma,2.7L,4wd,auto trans,113k miles
Former master tech, own Snap-on "brick" scan tool
Ran all factory manual and scan tool checks,no problem found. Replaced EGR valve, customer informs 1 wk later ck eng lt on, Code PO402. Ran all checks again w/no problems. Read your 12/30/05 posting regarding PO402 & VSV. Replaced VSV (always use dealer parts). PO402 the next day.
Freeze frame data after EGR replacement ECT(C)54,RPM 1,729,IAT(C)16,eng load 45%, veh speed 7 mph
Freeze frame after VSV - ECT(C)47,RPM 1,629, IAT(C)18,load 53%, speed 11mph.
Vehicle now has 117k, idles fine, runs great under all conditions. Suggestions?

Answer
As you know Po402 means excessive EGR gas flow but if that was the case there should be a rough idle, I think that there may be a problem with the EGR gas temp sensor, it may be giving the computer a false reading indicating a false temperature, make sure the electrical connector is good and not disconnected or has a bad connection,you can check the egr temp with the scantool, the specs are in the manual, if the temp is too high at idle the computer will see this as egr gas flow when there is no flow and turn the check engine light on, it's about the only thing I can think of that would cause this problem based on what was done already.