I have 1999 Accord Ex with the F23A1 and a 5 speed Tranny. The car has 196000 miles on it. When i depress the clutch and shift into neutral the RPM's drop down to around 250 and then slowly come back after i stop. i have replaced the distributor cap and installed NGK Iridium IX spark plugs to see if that hepled. The problem stopped for about 2 weeks and now its back. It might be a small issue buts its driving me insane. any help would be appreciated

 

See recent post 95 Accord LX 2.2 (Idle drops way too much when cooling fan kicks in). Your problem is likely indentical.

good luck

 

When was the last good TB cleaning?

 

My car did the exact same thing, and it's identical to yours. I can pretty much put money on it being the little Idle Air Control (IAC) motor/valve bolted to the back of the intake. Take the breather hose off and look in the throttle body there will be a little 1cm hole near the top of the throttle opening and close to the plate. This passage leads through the IAC.Try getting some throttle body cleaner and spraying it directly inside that hole while working the throttle back and forth, and it may fix the problem, depending on how dirty it is.

IF not, you will have to take it off and clean it manually. It's a PITA to get at but can be done if you have paitence. There is only two 10mm bolts holding it on and there is a vacuum line and 2 coolant lines running to it from the bottom. The best way to do it is leave the lines alone, because it would be near impossible (at least mine were) to get off without messing them up. just pull it out to where you can see it and spray it directly with TB cleaner and get some q-tips or a toothbrush and make it clean. Physically move the valve back and forth with a small screwdriver to clean it better.

I can post pics if you like; I have a spare one already off the car. If you take it off, check that the gasket is in good shape, and try to bleed the air back out of the cooling system.

Hope this helps!

 

Thanks guys. I really appreciate it. Do you mind posting those pics for me? Hopefully cleaning it with TB cleaner will help. Forking out $185 for a new IAC is rediculous in my opinion. We'll see how the cleaning goes this weekend.