I also have this problem along with other symptoms that are, I believe, related. After complaining to my dealer and getting no satisfaction, I pushed for more troubleshooting and the service manager made a phone call and made arrangements for an engineer from the factory to come and diagnose my vehicle (07 LE 4-cyl 5-speed AT). It took a few days, but I was finally scheduled and met with the engineer who flew in and rode in my vehicle while I demonstated the symptoms and he recorded them using a scan tool. It took about an hour to get all the details he wanted, but I believe it was worth the days work missed to get some motion towards solving this problem. The engineer advised me that it would probably result in a new MAP being developed and sent to all dealers to address part or all of this problem. He did not know what the time frame would be, but advised me to call my service manager in a month (three weeks this past Monday). I will let the forum know when and if a new MAP is released.
I wrote a short note to my dealer detaiing my take on the situation and am including it here:
1. When an attempt is made to accelerate with a slight push on the accelerator pedal,
the vehicle speed increases slowly. However, if the accelerator pedal is slightly
released from that point, the vehicle then speeds up quite nicely. (acts like
engine is lean or starved on initial accelerator.
2. With a little more than a slight push on the accelerator pedal, the transmission downshifts.
3. When traveling with the cruise control set, the slightest upgrade causes the transmission
to go out of lockup, then downshift, then accelerate hard overshooting the speed setting,
then coast while up-shifting and then undershoot the speed setting. Occasionally, the
process repeats and repeats until cancelled by the driver.
(My 2003 Camry LE - 4 cyl/4 speed AT never acted in this manner.
It stayed locked up in top gear even with a substantial push on the
accelerator. On trips through the hills of Pennsylvania and Virginia
the car rarely downshifted and maintained speed quite nicely.)
I didn't pick up on the hesitation situation until after I had the meeting with the engineer. I attempted to pull out of a lane of traffic and get into a faster moving lane. After signaling, I pulled out and hit the gas and the car just acted like I didn't press in the accelerator at all for about 1-2 seconds, and then took off like a V6. It has happened a number of times since. Thjis is a safety issue and could cause an accident.
