Please guys, let me know what you come up with. I am having the same issues with my fiancee's car. Anything under 2k rpm, the car is a pig, idles horribly. Once it hits 2,500 rpm all the way to redline, it wakes up (acceleration is good).
I took it to the mechanic, he didn't solve much. He replaced the ECU, nothing improved. He just wanted that car out of his shop. He didn't want to spend time diagnosing it.
I am actually changing the spark plugs, air filter, adding fuel additive, and checking for vac. leaks, (oil change and coolant flush too) . I should be done in a few hours. I will post what I come up with. It's been a pain in the ass.
We got this car months ago from some crappy used no name dealership in Hollywood,FL and it never ran well. (straight up thieves).
There were no warranties, it was sold as is, so we were stuck with this lemon of a Camry. I'm just trying to fix everything wrong with it.
If I could have it my way, I'd kick the salesman who pulled this fast one on my wife in the nuts

. (Good thing it's not our only car, but it's a PITA).