2007 Toyota Camry Hybrid

Noises problem
2007 Toyota Camry Hybrid 4 cyl Front Wheel Drive Automatic 87,000 miles

Over the past 4 years I have had 3 dealerships look into the following issues with no success. Originally at roughly 12,000 miles I noticed a slight knocking sound and engine shutter/car wobble when the car was initially started and the engine was cold. The shutter and knocking only lasted 5 seconds or so and only occurred when the engine first switched from electric mode to gas mode as indicated on the dash indicators. This problem was VERY seldom, I would say less than 4 times that year. I took it into the dealership each time this occured but they were unable to reproduce the problem but did document it for me.
Gradually as the car has aged and the mileage increased so has the frequency and severity of the issue. The problem has become so severe that now it is shuttering and knocking at 80% of the start ups regardless if the engine is hot or cold (severity is worse however, when engine is cold) and it even does it sometime when idling at a red light or in traffic now. To make matters worse I had the routine 90,000 mile maintenance (i have done all manufacture suggested maintenance to date) done 8 weeks ago and immediately following that I noticed the car failing to drop back into hybrid mode when idling. Sometimes it won't drop into hybrid at all during a drive and others times it seems to be fine. This culminated with me bringing the car in 6 weeks ago and leaving it at the dealership for two weeks to diagnose and fix the issue. I was able to duplicate the issue while in the car with their highest ranking tech and I was able to find a TSB report describing a similar issue on non-hybrid 6 cyl Camrys. After having the car for several days and looking into the report they called and said they believed that there was something going wrong with the trans-axle. Etc. So they replaced the entire transmission at no charge to me, even though I am out of warranty and do not have an extended warranty. Then upon starting the engine at the dealership to drive it home the same old shutter/knocking happened again. Although this time must less severe. So the service writer suggested that the new transmission need to be " broken in" and to give it some time and that it may get better. So here I am 6 weeks later and the problem is still the same and to make matters worse yesterday my A/C started blowing HOT air after sitting in traffic on the interstate stopped in traffic for over an hour and a half with my infant in the car. I had to pull over and call someone to help. Then upon restarting the car the A/C was cold again. I have never had any A/C issues in the past as a matter of fact the car has always been too cold!

Please, I hope that you can help me come up with some answers.
April 1, 2010.

This type noise is normally a bad main bearing or connecting rod bearing in the motor itself, usually on low mileage cars it's due to over revving an engine.(Red lining)

Apr 1, 2010.
Mr Merlin2021,

First I would like to thank you for your help. Second I want to point out that at no point have I intentionally " red lined" this vehicle. I am a stay at home mom with a small child and don't have time for that kind of foolishness plus I do try and take very good care of my vehicle. With that said I wonder how this could have happened. One of my complaints is that the car revs up to 0 miles per gallon when idling frequently and the engine feels as though it is reeving hard when this happens. This usually occurs at initial start up and when sitting in traffic or at a red light. I do not have a rpm gauge as the hybrid utilizes a mpg gauge therefore I can not tell what the actual rpm is at that time. Could this be the culprit?

A few additional questions for you: 1. Could there be something wrong with the computer that could be making the car reeve up like this? I should note that the dealership says they have connected the car to a diagnostic computer and it does not register an issue.
2. Would/should an issue like this show up on a diagnostic computer scan?
3. Is this a fixable issue? If so how difficult and costly?
4. Is this issue related to the A/C problem I experienced? If not, do you have any thoughts on that?

Apr 1, 2010.
All I can say about foreign diagnostics, is we now have N.A.S.A. Looking at the Toyota acceleration issue! You gotta be a rocket scientist to figure out some of this! Have Toyota listen to the engine with a stethoscope, no not kidding, we do use em! This will determine if the engine has these worn parts or not!

Apr 2, 2010.