Rodeo Trouble Code

Does anyone know (or could look up) what a P1406 code means in a '96 Rodeo 3.2L 4WD Auto Transmission?
I've gotten this twice in the past couple of weeks, both times shortly after
gassing up (filling the tank). The check engine comes on and stays on for about a day or so and then goes off. Engine runs a little roughly for the 1st half hour or so after the light comes on but after that it's smooth again.
Had Advance Auto read the code; their reader didn't give an interpretation it just said consult dealer or something like that.
Thanks in advance
Phil
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Probably EGR valve related, but could not find Isuzu specific info.

3.2L 4WD Auto

after gassing up

day or so and then

the light comes

it just said

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.