I have a 2008 Camry 4 cylinder with 170K that has been experiencing rough idle problems for about six months. Initially it started by idling at about 600 rpm with a definite vibration which I felt it just needed to relearn the idle speed (which I did). As the temps in Tx increased, I noticed the AC was having a very difficult time keeping up with the 100 degree plus temps especially at stops. With the AC on, the idle was noticeably worse. I did replace the air and cabin filters but the idle did not improve nor did the ac cooling. In June, I took it to my then trusted mechanic and they replaced the plugs, and performed a chemical fuel injector clean with little help to the idle. I then took it back to the same shop in Sept and found the guy who went to school with my wife had retired. During that span I monitored the gas mileage closely. I had been getting 24-26 MPG combined but noticed it had dropped to just over 20 MPG. The shop said the motor mounts were bad as was the ac compressor, alternator and belt tensioner. It did not make sense to me that the mileage would drop that much if the mounts, compressor, alternator and belt tensioner were bad but gave the OK to replace the mounts, alternator and tensioner (they wanted $2300 to replace the compressor, evaporator and other parts in the AC system). After so called repair, the shop guy tried to convince me it was better but the car was cold and idling at about 1.2K RPM. I took it home I found the rough idle felt MUCH worse than ever as the car warmed and idle dropped to 600 rpm as before. I then found a throttle body clean video. Before the throttle body I sprayed down the MAF sensor with Mass Air Flow Sensor cleaner with no help. I then carefully performed the throttle body clean as instructed with Mass Flow Sensor cleaner. I did notice that when my wife pressed the gas pedal down the butterfly valve did not open smoothly. Just as it opened at about 1/4" and before it fully closed at the same spot I noticed the butterfly look like it was sticking a little as it moved. It did fully open and close but just was not a smooth movement. After the TB clean, the idle was markedly better but still rough and a little more so when the AC is turned on. It is now idling warm at about 750 to 800 rpm instead of 600 as before. It may be a little sluggish from a stop but I can not really notice any difference in the way it drives. It is one of those oil burner engines from the era (about 1qt per 1K miles) even though I am a religious 5K oil changer. I'm also the original owner. We're in the middle of a home sale and purchase and need to keep this car running for another year. No codes have ever popped up for this issue and I maintain the car pretty well.