I just took a trip from TX to Ga pulling a 4000lb camper. I've pulled this camper in TX (no long straight roads) and never had an issue. With the Performance or Economy SuperChip loaded my truck would overheat on I-10 if running at 65mph, more so with the cruise set. The tow button didn't matter. With stock programming everything was fine. At steady speeds the cooling fan would kick up as fast as it could go, then the temp(coolant) would spike in 2 sec. then drop to mid way if I went faster or slower.

 

Does this happen on the Tow mode as well?

 

I'm referring to the Tow program, that is if you have the 1805 Flashpaq?

 

I've never tried the tow program, I'm only pulling 4000lbs. I think it's called easy tow on my programmer and it's made for heavy loads.

My programmer allows towing in all modes, Just different loads.

 

Most programmers would be willing to say that you can haul UP TO 8k on their performance setting, any more then that you would need to do their towing tune. As far as the overhitting goes, it could be related to the programming making your truck run too ho or their could be something else wrong; do you have an aftermarket water temp gauge to see how hot your running? Empty I'm running with a temp of round 200- close to 210 once, but only once, hauling 4k shouldn't bring you up too much higher then that if it all, unless your going thru the tx hill country(I know I-10 takes you into san antone so depending where on I-10 you were on you could be in the hill country, and I'm sure you hit some hills once you got past the basin in LA(I'm assuming you were still on I-10 there). Best thing I can actually suggest(based on just my experiance), if you have a call to run that trip again do it without the tuner for the entire time, if doesnt spike then I would be willing to bet it's the tuner, if it still does that for sure there is something else going on, or if where you are at has some harsh terrian take it out there and try to sim. as much as you can(load, road etc..) and see what that does without the tuner. Too many other variables to be able to rule anymore then that out.