Confounding idiot light

I have a buddy with a early 2000's TJ that has an issue. I'll have more details this weekend,but it throws a check engine light and begins to miss anytime the tank goes below 1/4. Fill it back up and the light resets and the miss goes away. Been doing this for over a month now. I'll see him tomorrow and we're going to pull the codes then. Very strange problem. This really sounds like an emissions issue, like a plugged vent/return line or something.

Idears?

 

You can retrieve the codes with the odometer.

Sent from my C771 using Tapatalk 2

 

Forgot about that Patrick, thanks! Unfortunately the vehicle is two counties away at the moment. We work together tomorrow afternoon, I won't be able to pull the codes until then.

 

Code scan came up with an open circuit on the #1 injector and (big surprise) a misfire on #1 cylinder. (I wrote down the codes and gave them to the owner) Nothing to indicate why the open might be occurring, or why it is only on #1.

I found a bunch of posts on the web about similar issues related to fuel level, but no definitive solutions other than keeping the tank filled above 1/4.

He's really broke and has guy that is local to him to help him out since I'm over an hour away from him. This is really odd.