Ok, this one is stumping me a little. Yesterday I was cruising at about 70 on the express way. Suddenly I get a backfire, followed by the SES light.
The car went in to open loop but other that seemed fine.
I pulled over on the shoulder to try shutting it off and turning it back on, hoping that maybe the backfire hat just confused one of the sensors.
When I started it up again my idle was flucuating between about 2400 and 3100.
I killed it again and popped the hood. Since I didn't have any tools there wasn't much I could look for, so I just checked to make sure the butterfly wasn't stuck and that the MAF was still plugged in.

When I started it back up it was fine and haven't had the problem since.
there doesn't appear to be a TPS problem.

 

A scan would retrieve the stored DTC code, and might tell you exactly what happened. Since you were able to determine that "the car went into open loop", you must have had some sort of scanner attached at the time. What did it indicate?

 

When it happened I did not have a scanner on it. There was only a slight change in the feel of the engine. From my experience, what I felt was the car switching to speed density mode. I was also under the impression that a car usually goes in to open loop (limp mode) when the SES light comes on.

Well, whatever.
I did actually put it on a scanner when I got home and couldn't find a problem. Than again I don't have a problem that can grab DTC's

 

hehe... that is... I don't have a PROGRAM that can pull DTC's