Car: 02 Accord, 2.3L 4cyl - 5speed, 80k miles

I've posted in the past about random stalling both at highway speeds and low-speed city driving.

I've read about the root causes being: main relays, ignition switches, igniters...

Current Symptoms:

It's hot and humid here in Chicago - and the symptoms are markedly worse.

At low speed driving, when I'm coming to a stop and have clutch pressed, the idle drops as the car is slowing down and just goes all the way to zero and the car dies. I can restart the car without any issues (restarts immediately, usually while still rolling). This has gotten much worse since it got hot and humid.

Maintenance I have performed (all using Honda parts)
1. Ignition switch
2. NGK plugs
3. Spark plug wires
4. Distributor cap rotor and gasket

I'm thinking it's a dirty/sticking IACV or sticking EGR valve. Any one have any thoughts on which one is more likely or anything else I can do to help isolate the problem one way or the other. The idle is intermittently very low/choppy, sometimes stabilizes. Having AC on/off seems to make no difference.

Thanks in advance for your suggestions/help.

 

Is CEL every illuminated or never? If yes, then get codes and post them. W/o them we're guessing.

Try connecting a vacuum supply line directly to the EGR from vacuum source w/ engine running. If this makes engine rough rougher or die, the EGR valve is opening on demand. If no change the EGR, may be stuck open or closed.

As possible solution, clean throttle plate (both sides) and bore of throttle body w/ throttle body cleaner. Remove and clean IACV movement.

good luck

 

Thanks for the suggestions - CEL is not on - is there any chance there are codes stored with the light remaining off (the bulb does work).

 

Its possible, but not likely that a code is stored.

Its free to have checked out at an autoparts store. While you are there, have your battery tested. I would check that all ends of both battery cables are clean and secure. Check the wiring from the alternator to the battery too. These are likely not your problem, but its worthwhile to be thorough.

 

Ok - so I spent a few hours this weekend cleaning out the TB/IACV/EGR and the idle seems much smoother and <keeping my fingers crossed> I have not had any stalls yet. The problem is very intermittent - so I won't believe it's fixed until I've gone a few weeks without issues.

There was definitely gunk on the IACV and the TB/butterfly-plate was covered in carbon/deposits. The EGR line from the valve to intake manifold seemed clear.

I was surprised as to how much coolant dripped out from the lines on the IACV/TB. I ended up just doing a drain/fill on the coolant and oil change while I was at it.

Thanks for the feedback.