i have had an rpm fluxuation for 8+ months and dies occationally at stops.

sometimes you can clean the iac valve and it will do the trick,sometimes not,have to replace sometimes.any vaccum leaks?any codes?which engine?

your oxygen sensor . if it is going bad it sends the wrong info to your sending unit if it is the sensor in your exhaust between the c.c. and muffler if there is something wrong like a hole in your muffler it sends a message to add fuel when really no more fuel is needed thus flooding out your engine then your engine sends a message causing it to decrease fuel thus depriving your engine. so you get fluctuations in your gauges but a range of reactions with your power as well

Did you ever figure this out? I had the same problem and after going to 7 different mechanics and spending 3,000 dollars with no results, I figured it out myself. In the end it cost me 39.99 and took an hour. It was the Throttle body position sensor. Very easy to change and makes the truck very smooth again. I realize you said you had the Throttle body "serviced" but did they change the sensor or just inspect and clean it?

Have you checked the throttle position sensor? My 04 1500 was surging up and down especially when I would brake. I also had transmission shift problem going into the overdrive. I changed the throttle position sensor and it fixed both