I'm new here (but not necessarily to cars), so go easy on me :-)

My fiancee's '99 Accord EX Coupe 4-cylinder automatic, with 130,000+ miles, has recently (in the past 3 or 4 days) started to stall out when coming to a stop. The problem first appeared while we were out of town this past weekend, and it stalled just as I pulled into a parking space at the hotel. The next morning I had forgotten about it, started it right up with no problems, and drove a couple of miles at highway speeds before stopping at a red light, where it stalled again. From then on, it chugged and bogged and choked every time I slowed down to a couple of MPH and I had to keep slight pressure on the gas pedal whenever I stopped to keep it from dying. When it did die, I don't fully remember but I think I had to give it a little gas with the transmission in Neutral to get it to start up again, and keep on the gas to keep it from dying. However, if we parked and left it off for a while then came back, it would start right up. On the highway (cruising and accelerating) it behaves just fine.

(A side note: we've known that the car eats oil (not leaks) for some time now, and I try to stay on top of it by checking every couple of weeks and topping it off whenever necessary. I've been negligent for several months and when this stalling started happening, I remembered and decided I'd check the oil level; bad news, barely even touching the bottom of the dipstick. I hit up a gas station and put two quarts in which brought the level back up to about 1/4 of the way between the low and high marks. Stalling issue was still there.)

We went about 60-70 miles on the highway before stopping at a service plaza to get gas. I bought a bottle of GumOut fuel system cleaner, poured it in (tank was ~1/4 full), then added 10-12 gallons (fuel gauge read Full). At that point, the situation seemed to improve. We stopped for lunch, and then again to pay a toll, and while it still seemed to be choking a tiny bit, it didn't stall. However, when we finally got home (fuel down to about 1/2 tank now), it started acting up again, although not as bad as it originally was. This was Sunday afternoon.

Since then, she's been driving it back and forth to work (about 20 minutes, 95% highway), and on Monday she said it didn't stall but felt like it was going to, Tuesday it did stall, and then again this morning it stalled. I don't think she's been having any problems getting it started in the morning or after work; it just stalls at red lights or when pulling in to park.

Now, I've done a good bit of searching (here and Google) and reading up, and it sounds like it could be any number of things. Main Relay, spark plugs, wires, distributor rotor/cap, ignition coil, fuel pump, vacuum, EGR, etc. My question is, how do I go about diagnosing this thing? She's had the car for almost two years now, and says she's always felt like the car sometimes stalls out when she's stopped at a red light, but I've never noticed anything when I've driven it or been riding with her. I don't know how old the spark plugs are, whether the wires are original or how long ago they were replaced if they aren't, whether the distributor has ever had any service, etc. I'm capable of doing the work myself (I've done brake jobs, replaced the thermostat and clutch master cylinder on my car, fluid changes, etc), so I'd like to avoid paying for a diagnosis and/or service at the dealer if possible since it'll probably save us a couple hundred bucks.

I'll have some time this evening to drive it around and narrow down a little more the circumstances under which it will stall out and how it behaves, so some guidance on what things to try to pinpoint the problem would be SO appreciated.

Thanks!

 

I would do the tuneup first (spark plugs, distributor cap, rotor, and air filter). Inspect the wires, replace if they are damaged. I would use dealership ones or NGKs. They seem to last for a long time.

If the problem still remains after the tuneup, try shaking the key with the car running to see if that gets the car to stall out.

 

If it was a flaky ignition switch, I think it should just flat STOP. No low RPM & feeling like it's GOING TO stall. It would act the same as if you'd turned off the key. Your description doesn't seem to match that. ????

After the tune-up stuff, try setting the BASE idle. I wrote some stuff about that over in the DIY section. Search for "surging idle" because a lot of the same things apply here.

 

Quick update...

Short version:
Took it to the dealer, they adjusted base idle and cleaned throttle body, and it no longer stalls.

Long version:

We ended up taking the care into the dealership while we went out of town for the weekend, and they adjusted the base idle and cleaned the throttle body and that fixed the stalling problem. They said the car still idles rough and that the plugs were pretty much shot, and suggested we bring it back when we had a chance for valve adjustment, timing belt (this has already been done but they didn't know that), 120k service, plugs, etc.

I changed the plugs myself (NGK V-power gapped to .044) and everything seemed to be good to go, but then a couple days later we were stopped at a red light and I noticed that it was still idling very rough... like it was almost stalling but not quite. I did notice that everywhere I looked online the gap for the car is listed as .044, but in the owners manual it says .040. Anyone have a definitive answer on that? I'm planning to do the valve adjustment myself (doesn't seem very hard, just need to pick up a set of feeler gauges and borrow some metric box wrenches), but haven't had time to get around to it yet. Haven't decided whether or not I should do distributor cap and rotor... any places I can look to determine if they need replacing or not (e.g. signs of wear, etc)?

Believe it or not, I literally just got an email saying that the CEL in the car went on this morning on her way to work. *sigh*... guess I'll be stopping at Advance Auto Parts to borrow the code checker...

 

Hey, thanks for the reply. I'll definitely keep that in mind.

My accord is getting taken to the shop today to take a look at the error codes. I did some more searching on the forums and it seems as though it could be the oxygen sensor which definitely seems plausible - it definitely can cause idling problems (stalling and rough idling).

I'll keep you guys posted.

 

So... where does this one (sigmaforce) come from? What kind of car? What's the original problem/symptoms? Why do you think YOUR problem would be caused by the O2 sensor?

 

Details are here:

I read about the O2 sensor from this thread: https://www.hondaaccordforum.com/for...ad.php?t=28426

My car is Accord LX 1998 4dr Sedan

Took it to the stealership and this is what they had to say:

- adjusted base idle with (hds) $85
- new EGR Valve Set Part# 18011-PAA-A00 Price: $165 + $144 labor

total cost: $417.19


error codes: p1491 EGR Lift Insufficient. EGR valve stuck open
p1399 misfire any cylinder
p0700 A/T system mal function p1739 pressure switch failure. recommend oil pressure switch


If the problem continues, I'll update the post.

 

Sigmaforce, where are you located? The thread you saw was a ULEV engine, in California. What engine do you have? Does it say ULEV-VTEC on the valvecover?

 

Hey Blake, my symptoms were exactly the same as the first thread in this post (ie, my car would die when slowing down and coming to stop lights). I have almost the exact problem described except my car is a 98 accord instead of a 99. Are you sure you want to move the thread?

 

Yeah, with the same symptoms, I guess you're right. So I brought your posts back here.
Sigma, was P1491 showing up before the fix or after? After the new EGR etc, any CEL or symptoms?

Now after I've caused all that confusion...
MJL, have you considered the EGR?
What error codes showed up this time around?