That O2 sensor performance chip is sounding kind of su****ious. Anything that has to do with O2 sensors can affect your fuel/air ratio. Maybe it's not working properly? Can you run your car without the O2 chip on? Try that and see what happens. Also you might want to check your new O2 sensor to see if you got a faulty one. Let us know how that works out.

 

the light should have a code associated with it that should still be there when you start back up.
right ?

 

My car never threw a code for the relay problem. So if you have a code you might have a different issue all together.

 

i'm having similar problems. the main relay looks fine, replaced fuel filter, the air filter is fine, recently replaced exhaust (including cat), and i can hear the fuel pump run when i turn the ignition to the 'on' position. the car starts and runs for about 15 minutes then stalls. it wont start again for 30 minutes to an hour. when it does start up again, the same thing happens. the problem started about 4 days ago and the car hasnt improved since. since i dont trust it enough to drive it after troubleshooting i've just been looking into one problem at a time (as listed above) then letting it run in nuetral. it seems to be getting worse. today i checked the ecu for trouble codes but it only flashed the code once (and of course i missed it). as it is now, if i let it sit for a while it'll start up, run for 5 minutes and die. sometimes it starts and does the same thing, sometimes it just turns over without firing. the few times when it dies on me while i was driving it would kind of 'hickup' intermittently first and i noticed the rpms were diving from 2500-3000 down to zero when it did the hickup thing. i've worked on civics for years and i'm baffled here. the forum has given me a ton of great ideas but nothing has worked so far. i noticed the ignition coil was mentioned in an earlier post, is that really likely? i guess anything could be possible at this point! any further help would be greatly appreciated. sounds like this is a common problem.

 

Okay, this is crazy. WAAAY to many people are going through this same ordeal, and no one has the answer??? Okay, here's everything that's happened to me. Hopefully something here can help. I have a 2000 Civic, with an automatic trans. No mods, totally stock. I'm the first and only owner, I bought it brand new. It's always had regular oil changes every 3,000 mi, and the timing belt was replaced around 90,000 miles. It now has 144,000 miles of HARD driving on it (distance and hills), and I've never had a problem... until recently. A few months ago, I started noticing that it would sort of kick or buck slightly when I was putting a strain on it, like going up a steep hill, or accellerating hard on the freeway. This seemed to happen mostly at higher speeds. It was rare at first, maybe happened once a week. But it became more common after a couple months. Soon, these little kicks started getting rougher, and more frequent. They became jarring shudders, and happened at least twice a day. My regular mechanic could not get the car to do it when he drove it. (Isn't that always how it goes?) The problem continued until one day, it completely stalled out on me on a city street, when I was going about 35 mph. It restarted immediately, ran just fine. It DID NOT pull a code. I went straight to my mechanic. He did a minor tune up since it never had one, and we hoped this would solve the problem. He flushed the fluids, replaced the distributor cap, wires, spark plugs, and belts. $210. A couple days later, I was maintaining a steady 75 mph on the freeway, and it bucked hard a few times, then the rpms just dropped rapidly. It acted like I'd completely taken my foot off the gas, but I hadn't. In fact, I feathered the throttle, and the car didn't respond at all, it just kept slowing down. I could put the pedal to the floor, and it was as dead as if the car was off. And suddenly, it sprang to life and leapt forward, rpm's shot up, and it ran fine. I turned around and headed back to the mechanic AGAIN. Only a couple miles later on my way to his shop, I was doing 65 mph and it did it all over again. But this time, the car never regained accelleration. No matter what I did, it just kept slowing down. And once it slowed to about 25 mph, the oil light and battery light came on. I managed to get it off the road. It wouldn't restart, so I called a tow truck. As I was waiting and trying to restart it, I figured out why the batt and oil lights came on. I realized that they had gone on because the car had actually stalled at once it slowed down to 25 mph. If you turn the key to the I position, your radio and stuff comes on. In the II position, all power equipment turns on, and all the lights on the dash come on, and some lights blink. If you wait a moment with the key in the II position BEFORE starting the car, the blinking lights (engine, airbag, seatbelt, etc) all go out. The only lights left on are the battery light and oil light. These only go out when the car is running, so that means they would come back on if it stalls. So that explains the two lights. My mechanic went through it again, and admitted defeat. I drove it home just fine. It was okay for a day, then it stranded me again, but this time it just stalled unexpectedly at a slow speed. I'd restart it, and it would run very rough, then smooth, then rough, and eventually just kept stalling unexpectedly. Sometimes even during accelleration. The as the rpm's are increasing, the gas pedal would suddenly just feel dead and the car slows and stalls. I took it to a honda specialist I know. He only works on hondas, and only uses factory honda parts. It's like going to the dealer, but cheaper. He said my exhaust manifold was badly cracked. He was right! It had a HUGE crack! (How did my usual mechanic miss that?!?) He said it was common in the late 90's and early 00 models. He said that might be causing the stalling, but it was unlikely. Either way, it needed replacement. It cost $650 (ouch), because it comes with the catalitic converter attatched. They don't come any other way. He also said my ignition coil was burnt up, which could account for some problems, but also unlikely. The coil alone could cause the car to act like that, but he said he still thinks the stalling was due to something we still hadn't found yet. Still, the coil had to be replaced either way, so I had it done as well. Another $75. He said it would probably act up again, since he didn't think that was the root of the problem. But the car ran great! ... for a week. It died again, but this time the check engine light came on. The honda guy said it pulled 2 codes. One was PO420, and I can't remember the second one. But PO420 is the secondary O2 sensor (the one after the cat), and the other code was for... the catalitic converter! Right. So we replaced the O2 sensor. $225. Had problems right away. Stalled. Check engine light. The code was for the cat again. I know it's not the cat, it's brand new! Now the honda "specialist" is stumped too. I'm managing to still drive it around, but I know it might die on me anytime, anywhere. So I'm trying to avoid freeways, busy streets, and long trips, but I can't do this forever. But as I've been babying it around town, I've noticed a pattern: it seems a lot more likely to studder and stall if I start the car and immediately drive it while it's still cold, or still warming up. And once it starts the stalling pattern, that's all it seems to do until it cools back down for a few hours. However, if I start the car and let it idle and warm up for about five minutes before driving it, it seems to run okay as long as I don't drive it hard. So if I don't accellerate hard, drive too fast, or run the a/c, it seems to do okay... so far. But I shouldn't have to drive like a grandpa just to keep my car alive! I haven't tried checking the relay yet (mentioned in prior posts), but I will look at it. I doubt that's it though. I also read in other topics about an IAVC. What is that? Is that like an idle control valve? Whatever it is, it seemed to cause similar problems, especially with people having trouble starting their cars in hot weather, and trouble keeping them running. Could our problem be related to this mysterious IAVC? This is my only mode of transportation, so I've missed a lot of work due to it's unreliability, dropped a lot of money that I don't have into parts that aren't helping, and I'm really frustrated and now b

 

thats a really long post^^^

 

is this a thread from the dead??? whatever... sounds like the main power relay in the cabin.. which heats and cools...damn japanese ppl didnt know how to soder right when they made our hondas.. have that looked at.. search google for it theres ways to sodder fix it

 

http://techauto.tripod.com/mainrelay.htm

 

A quick check for all of you is to pull an injector. Then check your ecu and see if it throws you a code for it. If not then get a new ecu and that will usually solve all your problems. Most people overlook the ecu as it usually isnt a problem but hey, ya never know...

 

for a problem like this - a person needs some troubleshooting tools.

whenever is stops and does not start - then right away you need to check for spark. that will tell you a lot.

here is what i use. i have an electrical cable (wire) with a clip on each end. if it is 6 feet or so long - the more the better. take out one of the spark plug wires. i also carry an extra spark plug. that is not absolutely needed, but then you do not have to take a spark plug out (saves time and work). connect the spark plug cable to the spark plug. then i connect one lead (clip) of the electrical cable to the threads of the spark plug and the other end to ground - you can ground off of the engine, or better yet to the neg at the battery. if no one else is there with you, you have to position the plug so that you can see it when sitting in the car and cranking the engine. i usually set it on a rag - then go in and crank the engine and you will see if a spark jump the gap. lets you know if you have spark or not.