Cruising speed throttle issue during warm days

I have a '90 XJ 4.0 with 200K/auto. When the outside temp is above 75 degrees, at cruising speed, it dogs down briefly a few times, then recovers. It will repeat this process for about the first fifteen minutes of operation on the highway, then seems fine until I shut it off and restart it. This does not happen during the cooler evenings. Seems like a fuel delivery issue, but not sure what would cause that to happen only during warm days outside? Any suggestions would be greatly appreciated! :smsoap:

Check out my renix issues thread. I'm having similar issues with the exact same setup. These guys have kicked around some really good ideas and I'm currently working on their suggestions. I don't know if its strictly a 1990 issue but it is frustrating as hell. If you figure anything out I'd love to hear about it.