This problem has been bothering me for a while and I have tried a few basic things such as replacing plugs, air filter, and I tried checking the EGR with the "pinch" test because I had read that may cause this problem. But, I got the clicking sound, which supposedly means it is working.

When I come to a stop, the RPMs drop low enough so that the car shakes for a few moments, and then returns to normal. It has not stalled yet, but I fear it will. I have noticed that it occurs much more frequently in the summer, and also more often after I have driven the car, parked, and then started it again with the engine warm. It does not seem to happen when the A/C is on, but after it has been shut off, the problem will occur, or may be worse.

In addition (I don't know if this may be related), at my last SMOG check, the NOx measure was high. The car passed, but the measurement looked unusually high to me (I don't remember the exact number).

Any ideas?

Thanks!

Couple of thoughts:

. Start using full-synthetic engine oil in your Civic; e.g. Mobil 1 5W-30. Emission test results are much better using synthetics. My 13 year old Civic's emission tests are like those of a new car. It has only used full-synthetic engine oil from the beginning. The engine will also perform better, get better gas mileage, and last longer.

. Your idle speed is too low. Read the link below and see if you can use it to adjust your idle rpm:

https://www.askmehelpdesk.com/cars-t...tml#post219948