It's looks like I'm having transmission problems now... Issue started several weeks ago. About 6 weeks ago, I noticed that when shifting, the RPMs would drop to about 1500 and would oscillate by about 100 RPM. Then, slowly, every day this oscillation would get more extreme. About 2 weeks ago, it was oscillating by about 800 RPM. So, I figured it could be the TPS, so I replaced it with a spare TPS I had. I also cleaned the MAF. Problem went away for about 3 days, then started oscillating by 100RPM. So, I took it to a local transmission shop. I made two mistakes there. First mistake I made was talking to the wrong guy. (There are two guys that work in this place. One of them is the best transmission rebuilder in the area, the other guy... well he didn't even know what a differential or a 4t65e was the last time I was in there.... ) Second mistake was telling this guy what all I had already checked, so of course he went straight to "oh, it needs a rebuild". Which it very well might, but I can't take this guy seriously when he tells me he could remove the pan and filter to get a look at the TCC solenoid before tearing it down completely. TCC solenoid is behind the side cover, though. The second shop I took it to, when I told him about the TPS, he claimed it needed reprogramming, which costs $45. From what I understand, though, the TPS is non serviceable! And those are the only transmission shops around here. So, not happy with what I was hearing, I replaced the TPS and the IAC (IAC seemed to finally fix my occasional hard start at least!) with brand new ACDelco parts from Amazon. I soaked the MAF in MAF cleaner. I did this on Friday. Drove great for about 30 miles. Shifted like it was a brand new transmission. After I got back, though, I found a TPS low voltage code (no CEL). I cleared it, because it must have been when I had the ignition on, with the TPS unplugged, because that code has not come back. Saturday, drove about 12 miles, everything was great. Yesterday, I drove it about 8 miles, with 4 more to go, and that's when the problem returned. Last night I found on Triple Edge Performance my exact issue. They refer to it as "TCC RPM Oscillation". They say it can be as simple as a dirty MAF, to valve body and bad torque converter... So, has anyone else had this problem? If so, what was the cause? Am I going to need a new transmission?