I know it’s difficult to diagnostic a problem without a DTC code. I just want to know possible causes for this type of symptom.

Don’t take it wrong, the transmission was replaced for other causes which are no longer on my car since replaced. I was hoping the low RPM problem will go with the Transmission replacement. But after the Transmission was replaced by Honda, this problem still persists. Honda could not do anything about this specific problem since they can not replicate it, when testing my car.

Here is a summary:

Symptom / Info:

1. At least 1-3 times a week, and when I come to a sudden stop (like signal lights) the RPMS goes very slow like 250; then the car starts to rattle as if it is going to turn off. But when I pressed a little on the gas pedal everything goes back to normal (over 750rpm). It’s like the car is chocking or like when you depress the clutch pedal on a manual without pressing the gas. At first I was under the impression that it could be transmission related because its seams like the car is in “2nd” gear and could not switch to “1st” until I press the gas pedal.
2. My car does not have the Check Engine light on.
3. My car exceeds the 80K extended warranty on EGR (95K at the moment).

As some of you pointed, this could be related to the Throttlebody / EGR but:

1. How probable is that it could be the EGR valve?
2. Does cleaning the throttlebody with seafoam automatically clean the EGR valve?
3. Is there anyway to isolate and test the EGR valve for malfunction?
4. Is the EGR located on the “throttlebody” (view diagram below)?