How's it going guys. Been looking around and have found a quite a few threads that are similar to my situation, but not exact. I'm hoping someone can help me diagnose my issue here.

Basic information. The car is a '99 4-cylinder automatic. My problem is that the car will stall on occasion when I bring it to a stop (stop sign, red light, etc). Once the car is in motion, it drives perfectly fine. But if you stop the car, the engine will either stall, or the RPM will drop very low and it will catch itself right before it stalls. The part that puzzles me is that it doesn't do it every time. Some rides it happens every time you stop, some rides it doesn't happen at all.

Also, when sitting at a stop, if you put the car in neutral and give it a quick rev then let the RPM drop, the engine will experience the issue.

I replaced the spark plugs today and took the car for a drive in an attempt to get it to stall; couldn't make it happen. Tried breaking hard into a stop, slowly into a stop, just couldn't get it to do it. I doubt the spark plugs were the problem, but I could be wrong?

Anyone have any insight here?

Thanks.

 

Since you can't get it to stall now, I would wait and see if the spark plugs fixed the problem. Let us know what happens.

 

Honda idle-control system is finicky about how it's set up. Look in the DIY section for a post by me about setting the BASE idle.

 

I took a look at the post and will surely give it a try, but I do have a question. Can the settings for the system change over time? Just curious as to why I'm suddenly experiencing this issue now, when I've never experience it before (just passed 100k).

Edit: Never mind. Seems as if it can get dirty, causing it to fluctuate. I'm going to try cleaning it before I adjust anything, unless you recommend otherwise.

Double Edit: Unless I'm mistaken, the IACV is on the back of the intake manifold, facing the back of the car. Is there a convenient way of getting to it without having to remove the whole manifold?

 

You can try a boxed wrench on the two bolts to remove them. Then just clean the IACV with the hoses still attached.

 

Stuff gets dirty & that affects the idle-control. So YES, clean it then set the base idle, then force it to re-learn like in that post.

If you're lucky, cleaning will restore everything. Occasionally the IACV can actually go bad, but you need to try cleaning it first (cleaning most likely will fix it). But you see in that post where you reset the ECU to force it to re-learn... Over time, it slowly "learns" how to deal with the dirty throttlebody, dirty IACV, ect. You need to erase all that "bad learning".