Suggestion needed - Engine stalling occasionally.

99 accord, manual, 5 spd.

When I depressed the clutch, the RPM normally drops to 700 quickly,
which is good. But occasionally it drops to 100 or lower and then rises
to 700 slowly. Sometimes, it's so slow that the engine stalls
(smoothly). After I turn the key to retart it, it runs OK again.

I doubt it's the Idle Air Control (IAC) valve's problem. But I don't
understand why a restart makes the problem gone right away.

Anybody has any idea?

Thanks!

 

wrote in

No, it drops to 500. Everybody thinks that bottom line is 100. It's 500.

Check:
1) Coolant level in the RAD
2) Check the cleanliness of the throttle body

 

Bad launches can mean that the O2 sensor has failed or you're running
very rich while the ECU isn't using O2 sensor feedback.

 

Same thing happens to my 92 civic dx. What does the coolant level and
throttle body cleanliness have to do with this? I've cleaned the whole
intake manifold and throttle body, replaced the PCV valve, cleaned the IACV
and FITV, and it's still doing it even though the idle has stabilized a
little (PCV was really dirty).

It still dies from time to time.

I know when I taking off, clutch half way depressed, in first, sometimes the
"engine died" light shows and it's like the engine dies, but then it
restarts and when I give it gas it continues smoothly. Do you think the
clutch needs replacement and is causing this?

 

The problem happens to me when I slow down, not take off.

The clutch was depressed all the way down to the bottom. So, I think it
shouldn't be a clutch problem.

 

Oh, then it's probably the mechanical idle setting. If it's set too
low, the engine can stall when you push in the clutch. The electronic
idle control takes a moment to open so it won't catch rapidly falling
RPMs. My 97 Civic needed it adjusted when it started stumbling on
clutch depresses.

The clutch is easy enough to test. Shift into reverse very slowly and
listen for grinding.

 

and in this vehicle, the ignition switch - a recall item.

 

Kevin,
If it's the idle setting, the prooblem should happen more frequently.
Right?
In my case, it just happens occasionally. I started to have this
problem about 6 months ago. The problem has been getting worse little
by little.

Jim,
My iginition switch was replaced by my dealer.

Thanks.

 

on my 98 civic, a bad O2 sensor gave me a check engine light, and it
would die at idle. if you have an older civic with the original sensor,
might be worth replacing.

 

Well, it doesn't die completely. It's like the clutch catches on but then
I'm thinking there's not enough power to go on and the dead engine light
shows, so I immediately give it gas, and it returns back to running.

I'm thinking the stalling (as the OP mentioned) and this problem on lunch
are two separate issues--I'm concerned about both.

 

You mean the idle adjustment screw?

 

The thing is the light goes off, and the engine restarts if I press gas
right away (as soon as I see/feel that the engine is dying).