Hi,

I have a 2001 Honda Accord 2.3L 4-cylinder F23A4 engine. The car starts fine and idles nicely at 750rpm-1000rpm when in PARK, that is, shift stick in park. When I rev up the engine, the idle speed would drop down below 500rpm and seems not able to go up back to 750-1000rpm. I do *NOT* have this problem when I drive the car.

I am going attempt to clean the throttle body to see if that helps, but I would appreciate any input.

Thank you very much!

 

Cleaning the TB is good first step. After you drive the car and you put it into park, does the idle still behave the same way? Is your check engine light on?

 

Thanks for the response. Yeah, going to clean throttle body this weekend, but to answer your follow-up question. After driving, the car idles at 750-1K rpm (very good) and no engine light on. Anyway, I replaced the PCV valve and hose (an OEM part) a couple days ago, and I am glad I did. The old one is 23 years old! And when I shook it, I didn't hear any clicking noise like a working PCV valve should be, which the new OEM one clearly has the clicking sound when shaking. Took the car out for a drive this morning, and I don't see the idle speed fall when reversing. Regardless, I need to clean throttle body and also check the air intake temperature sensor as well to make sure if it works correctly.

I replaced the PCV valve, because after a lot of research I read that a bad PCV can cause a lot of problems (due to pressure build up), including rear main valve leaking, which unfortunately my car recently just started to experience. Hopefully, the new PCV valve will help. This OEM part and its hose cost a total of $37 and it is so important! Don't forget to replace yours, folks!

 

Cleaned the throttle body without taking it out entirely, just taking out the air intake plastic conduit. I used carb cleaner sprayed on strips of clean rags. Cleaned the inside and the edges and surfaces of the butterfly, the flap that opens when another helper gently pressed on the gas pedal and held for cleaning. I did not feel it's safe to spray the carb cleaner into the throttle body itself. The idle speed stays constant (750-900rpm) when reversing or idle and coming down to 750-900rpm when releasing the rev'ing. That's good!

BEFORE



Strips of rags. I made them long and sprayed generously at one end with carb cleaner. And cleaned the inside of the throttle body. Then I cut that little end piece of rag, because it gets dirty. And repeated the process.

THE RAGS

Dirty on both sides.




AFTER

Very important to clean the edge, the surfaces, and the hinges of the butterfly, as well as throttle metal tube itself, as much as possible and GENTLY!!!