For about 6+ months, primarily on the highway, my RPM's have been intermittently surging - anywhere from 500-1000 - and then falling back down. When the issue started it was less apparent. My first thought was change the air filter. I took it into the shop for inspection and the mechanic found nothing. They checked my tranny fluid (said it looked good) and also opened up my cluster to check that all the wires where in tact - and I wasn't throwing any codes. I guess I didn't have an immediate concern because it's my secondary vehicle and typically just driven around town. The last month or so it seemed like it was happening more frequently so I took it in for a tune up. My plugs were shot and EGR was pretty gummed up. From what I was told my fuel filter could not be changed because it's located in the tank, so it could only be flushed (FACT?). I noticed an immediate fix to my fuel economy and it seemed to have a little more pickup. But I guess I expected the surging issue to go away and now I feel like it's even more noticeable - even in cruise control on a flat surface.. and it seems like it's taking longer to switch gears when getting on the highway.. I'll run 3000+ RPMs before it shifts. I took it to Auto Zone for a code reading just in case - nothing. They told me to start with flushing my tranny fluid, which I have no idea when it was last done.. I bought the truck at 91K and now have 120K+. My fluid looks good, it's red, the appropriate level and doesn't appear to have any sludge. As I continue to research the issues via the web and consulting friends, I've come to the following potential conclusions listed in order of what I think is most likely, (and I'm no mechanic).. 1. Throttle Position Sensor 2. Just needs a tranny flush 3. CAM sensor 4. Throttle Body needs cleaned 5. Bigger issue with my transmission Note: I am not hearing any real knocking or clunking, etc. Sometimes I will hear a little knock when I make a more abrupt slowdown/stop. But right now the only issues I'm noticing is with the surging.