Hi,


My 99 Civic LX (4 SPD Auto) with about 145k miles has been stalling intermittently for almost three weeks now. My mechanic had it for more than a week and could not get it to replicate the problem when he drove it around town on parts runs. He's trying to help me out by not just replacing parts until something works, but actually troubleshooting.


I took it back for the weekend and of course it started stalling on me right away. I'm researching and reading threads and not smart enough to reach any conclusions.


Here's what we know:

• distributor was replaced at 125k miles. Previous owner fried it by putting in the wrong spark plugs (DIY noob) right before he sold it to me
• O2 sensor has been replaced - we don't know when, but clearly not the original
• it's not throwing any codes
• mechanic says the IAC valve is fine
• No obvious vacuum leaks or frayed wires or anything like that
• he replaced the spark plugs just in case, didn't help

Here's what it does:

• Stalls at highway speed. It's done this twice, once at 65 MPH after cresting a hill and letting off the throttle for an upcoming stoplight, and once at about 45 MPH accelerating from a break in stop and go traffic
• Stalls in stop and go traffic. This is the most common situation. My daily commute has a 10 mile stretch that is often backed up to 30-35 minutes. There's one major merge point where it almost always stalls at least once (and for about two weeks prior to all this, it was stuttering without stalling). This comes about 10 minutes after I've left the office - this time seems significant. Once I start it back up and traffic starts moving, it doesn't stall again
• Stalls after a slow, hard turn. It's done this several times.
• Occasionally (1 time in 3?) won't start after it stalls. Every time this has happened, it starts back up within 1-2 minutes.
• One time only, wouldn't start in the morning but started fine 5 minutes later. Then it stalled three times in the first mile. That's when I took it to the mechanic. It did the same for him the first day and then ran perfectly for a week straight, even though he'd done nothing to it.
• When it stalls, the battery light and one other red light (temperature?) on the dashboard come on, flicker once, and then stay on
• Idle is a little rough at low RPMs but no obvious problems and not consistent. If it starts to idle rough, that's my clue that it's probably going to stall at the next slow down, stop, or turn

Anyone ever experienced this combination of issues? My mechanic is a smart guy, certified Honda specialist (if that means anything) and I think he's doing a good job, but I can't wait this out indefinitely.


Also interested if anyone has any thoughts on trying to sell it AS-IS. KBB right now is $2500 in good condition and wondering if I would come out ahead if I sell it before putting several hundred into it.

 

Check/set spark timing with a light needs to be done after distributor replacement.

The most common reason for idling too low and stalling out (though still always driving OK when you press on the gas) is dirt in the IACV. This valve is located on the side of the throttle body, remove and clean with spray carb/TB cleaner.

Stalling while driving and then refusing to restart for several minutes can be the ignition control module intermittently quitting when hot. You need to check if the sparks are firing during the time that it will not start.

The "oil" and "battery" lights on the dash normally come on whenever the key is on but engine is not turning, this is a good sign. If the lights don't come on the stall was likely due to a bad ignition switch. Some Civics possibly including yours have been recalled for new switches.

 

Thanks, that makes sense.

Would the IAC valve also be a factor in not starting when cold? Just tried twice this evening and it won't start at all. Good strong crank and all the lights on. Just won't fire.

Recent experience says it will start fine next time I go out there but I'm wondering if we're dealing with multiple problems.