Originally Posted by goaman
Actually, the Honda mechanics could simulate the problem but they just can't tell me the cause. I don't know if the following could help you understand my car's problem better:
When the engine is cooler (when I start driving) it doesn't jerk and only when the engine got warm up (5-10 minutes later), then the jerking will be obvious. Also, when it jerks, if I accelarate, or shift to D3, then the jerking would stop.
Anyway, I'll be sending my car to one of the outside mechanics that uses diagnostics program that could help to identify problems.
Please, by all means inform me should you have any clue. Thanks!
Way outside guess here but let's see how close I am. It sounds like it might be the torque converter locking and unlocking. I base that theory on;
1. When you accelerate or downshift the PCM automatically commands the TC to unlock.
2. The PCM won't let the TC lock until the trans fluid reaches a certain temperature (not sure what that is on your car, probably around 150F).
3. In D4 at that speed range the engine is running at a lower RPM so it would be more noticable than a higher speed.
Now the question is what the root cause is, and that could be several things. Let me know what fixes it and how close, or far off I was.