Started acting up about a year ago in high degree temp weather (over 95). Low gas to just hold speed around 40 - 50 mph. Overdrive will appear to buck the transmission every so often. Can disable the overdrive and it will go away. Haven't taken it in yet to see if they can troubleshoot as I have a work around. With the new summer, it has appeared again and seems to be getting a bit worse.
Truck has 130,000 miles on it and transmission fluid was recently changed and flushed. Needing to get sparks replaced as well, but don't think that is the cause. Brother-in-law had similar situation and apparently it was due to some sensors, but haven't been able to get with him to fully discuss what he did, and if it actually meets my issue. Any help would be appreciated.

 

Yes, spark plugs will do exactly that - light throttle in OD between 40 and 50 it will buck and miss. 130k is twice the recommended life of the spark plugs.