Okay, Saturday on our trail run my truck started running chitty. Wouldn't idle, and I had to adjust the curb idle way up to keep it running. It was kinda what I would describe as "loading up". It smelled rich, too. Engine temp was normal 180°. It was running fine at the start of the trail, but I shut it off at one point, restarted and it was running like poopoo. Never had any problems restarting the truck, just keeping it running. Course the next day we get in to drive 3hours home, the truck runs fine all day. This happened one other time running around town all day, stop and go. The truck started running bad. It was parked for several days and the next time I drove it, it was running fine. The carb was rebuilt in January and has only a couple hundred miles on it. Here's some of my thoughts: Vapor lock Fuel pump is borderline, and when idling a lot it starts to fall behind. Float sticking. Float level too high. Something other than the carb.