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I have 2000 Honda Accord V6 with 140K miles and which is very well maintained and runs really nicely. However, every once in a while when I start it it would do some erratic rpm changes on idle and then stall. If I manage to get it moving despite rpm drops, it runs great and would not stall again. Also, if I leave it for a while (like 15 minutes) and then come back, it usually starts like nothing happened. For last 3 years it was doing it 3-5 times a year but now it started to happen more often.

I tried few times to raise idle RPM to 2K-4K and that ended up with CEL coming up. OBD codes would always be the same: P0300 (random misfire), P030X (Cylinder X misfire for X being any and all cylinders) and pending P1399.

In the Honda shop, when they saw those codes they said that according to procedure they need to replace fuel regulator and PCM and if it didn't help, injectors and some other things. Essentially they have no clue and I am reluctant to pay a lot of money just to experiment.

I recently replaced spark plugs and timing belt was replaced on schedule as well as all other maintenance requirements.

So I am getting desperate and wonder if anyone had similar symptoms or an idea of what may cause the problem.

Thank you

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Does this occur when the motor is warmed up and then shutoff or first start of the day when the motor is cold? –  mikes Mar 9 '12 at 2:30
    
It happens when the motor is warm. Usual scenario - go to the store and when you want to leave parking it happens. Although it seems to always be somewhat cooled down. Like after 15 minutes in the store. –  Uncle Meat Mar 9 '12 at 6:22
    
I have the same problems. No codes are coming up. I've changed the starter and battery. I didn't have any problems before, but now the car will idle at just 200 rpm. –  user2135 Aug 23 '12 at 15:55

10 Answers 10

Sounds like a fuel delivery problem. Replace the fuel filter and run a bottle of fuel system cleaner through it. If that doesn't fix it, then at least you know it's a more serious problem (probably a flakey FPR).

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So the problem seems to go away if manage to get the car into gear and move, but not if you rev it?

"fuel ressure regulator and PCM!?" Sounds like they haven't bothered with the slightest bit of diagnosis. It sounds like a fuel pump problem to me. An electrical fuel pump problem at that.

I think you have a mechanical fuel regulator, so i wouldn't expect it to play up in such an intermittent way.

You should also be able to hear the pump running, normally, with careful strategic head placement. Once you find a spot where you can hear the pump, try to reproduce the problem and get someone to start the car while you listen.

If it's not running and you are handy with wiring tap the fuel pump positive side and see if it's getting 12V when the problem occurs. Keep the other end of the tap in the cabin. If it's getting 12V then you've narrowed it down to the pump. Otherwise move on to the relay.


Before you get dirty with the diagnosis you might want to preemptively replace the fuel pump relay. These can fail in a temperature dependant way. Heat soak after you stop will probably be the highest temperature a relay in the engine bay will see.

It seems like Honda has had a lot of problems with relays failing when hot. Search "2000 Honda Accord fuel pump relay". It looks like the main fuel (pump?) relay under the dash might be the culprit. Here's one guy that solved it.

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I was having the same problem with my 2000 Accord coupe v6. Has always been an intermittent problem. Just got it from dealer I experienced shaking on highway one day cruising at 75 mph, freaked me out. Check engine light came on and was P0108. Map sensor was somehow not fully connected. That took care of that. Regarding the no start after "hot soak" they replaced bay one O2 sensor. Still didn't solve issue. Then their tech line referenced SB 00-024 in regards to winter fuel. They added a BG Ethanol treatment and filled it up with premium gas and so far so good. Recommended repair would be to replace the PCM and Fuel Pressure regulator. Told me to check out www.toptiergas.com to locate stations with proper fuel. Told me to go to high volume gas stations and run premium. The car has 209000 miles and never had any issues. Gonna try out the high dollar gas for a while and hope it doesn't come to that. According to some info I found here: http://www.motobild.com/honda/2000-honda-accord-v6-match-fuel-pressure-regulator-with-pcm.html my vin # indicates that I should have the updated PCM and regulator. I am at a loss.

  • KM
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I had the same problem you have to change your control box more or less $ 100.

Hope this helps, mine runs perfectly since replacement.

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Is it main relay? –  Uncle Meat Apr 5 '12 at 6:51

I had this same issue. The PCM and fuel pressure regulator is the correct fix. It is not cheap, but it does address the problem.

If i recall, the issue has to do with ethanol having a lower boiling point than traditional gas. This causes it to vaporize on the fuel rail when the car's warm, but no long pumping gas because it's off. When you go to re-start the car, instead of liquid gas, you are spurting on fumes on the rail. Once the car cools sufficiently, the vapor recondenses to liquid so you can start again.

The new PCM and fuel pressure regulator (i think that's what it is) creates a higher pressure inside the fuel system and the higher pressure increases the boiling point of the fuel, eliminating the problem.

I had issues with taking the gamble on this fix, but it did fix the problem. There is even a TSB on the issue.

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Good answer: do you have a reference for the TSB? –  Bob Cross Jul 18 '12 at 16:24
    
thankyou danny yang for the help. your answers was 100% correct on the ECM & fuel pressure regulator. I replace the ecm with a newer one and fuel pressure regulator. you are right. it is not cheap. $300.00 total. it is also solved the P0171 code on 2000 Honda accord v6. –  user4665 Mar 9 at 4:54

I have an accord ex and have had the same issue and replaced the relay under the dash and have not had a problem since until recently, so I am now going to try the throttle position sensor or the idler sensor. Hope this can help someone with the same issue.

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2  
Which relay did you replace? –  Mark Johnson Dec 4 '12 at 2:47

I had the same problem with my 1998 Honda Accord (6th gen.). My check engine light kept coming on so I took it to a local AutoZone store to check the error code which turned out to be p1399. And the sales associate told me what the code meant and that I needed to replace my transmission shift solenoid. I ordered the part ($350 and some change). As soon as it comes, I’m going to have Honda dealership put it on for me, and pray that it stops the problem. Hopefully, this was of some help to you.

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I had the same problem with my Honda Accord V6 for a while. The person who owned the car before me had been running on premium gas. When I tried using super this did not happen again for a whole year. It did end up happening again, but this may have been because of some of these cheap gas stations I go to. I would say try out the highest grade for a month or so and see what happens, I am pretty sure it will solve the problem.

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I tried expensive gas from good stations for a while and it didn't help. It seems related to winter blend of gas somehow as someone suggested. –  Uncle Meat Mar 11 '13 at 23:46

It's overheating! Hot Soak! The 2000 accord has the fuel rail under the intake manifold and right above the engine. The hottest possible place it could have been put. I replaced my 12 year old thermostat with a new one from Honda (167 degrees is the rated temp. for this year) and problem solved!!! Then, a few weeks later, it started again... but this time it was the air-conditioner fan relay. Second fan was not coming on. Replaced the relay ($7.35) and good to go. Been over a year and no problems at all!

Simple cause, simple solution... OVERHEATING!

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So eventually car started idling really bad and CEL light came up with P0505 - Idle Air Control Malfunction. Did some diagnostics myself and took it to the shop. Conclusion was that IAC needs replacement. So I got it done and the adviser said that previous stalling problem was also caused by this. So far so good. I will accept my own answer once I confirm through the winter that the problem got resolved.

On a second thought, if someone is experiencing the same problem, you can just disconnect IAC wire and see if car will keep stalling. If it's not stalling with IAC disconnected than I would say it's IAC. Can't test it myself until it happens again.

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