Check engine light on & off whenever truck is "working"

2004 2.7L 4x4 5-spd

I'm getting a check engine light that will come on whenever the truck is "working harder than it might want to..." I know that's a lame way to describe it.

It will come on during a real hott day of driving around town with the AC. It'll come on when I'm towing. It'll come on if I'm sitting it traffic, on&off the clutch for a while. It never comes on though during a long highway ride, or just normal around town driving.

I know this probably isn't much help without having the code read. But the light keeps going off a couple hours after I turn the car off, so I never get a catch it while it's on to read it. The temp gauge never runs high or anything, I really have no idea what it could be..

Anyone experience this?

 

My wife camry did that and the dealer claimed she didnt put the gas cap on correctly

 

Yea. I suggest trying to get any ODB error codes. Go to the auto parts store to borrow the reader.