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RIP, Lead Technician
Category: Honda
Satisfied Customers: 5591
Experience:  Master ASE technician, Honda/Acura aftermarket training, Hybrid training, Adv. level L1
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2000 Accord: P0301, P0302, P0303, P0304, P0305

Customer Question

2000 Accord w/3L V6. Developed constant misfire yesterday am. Ran ODB resulting in codes P0301, P0302, P0303, P0304, P0305, P0306, P0300 and Pending Code P1399. Had similar situation last year following extreme cold weather <10F. problem resolved by two cans of dry gas. We had 2-3 days ov <15F preceding problem

Has 133K miles but typically runs like brand new. Timing belt replaced at 85K
Submitted: 9 years ago.
Category: Honda
Expert:  RIP replied 9 years ago.

Hi, welcome to Just Answers.

Sounds like you may have a problem with your EGR valve and clogged EGR ports in the intake manifold...this is a common problem on Accord 3.0L..has the EGR system ever been serviced in the past? On higher milage engine's, I've had to remove the intake completely from the engine to clean out the EGR ports. Basically what is happening is the EGR valve is staying slightly open and allowing the exhaust gasses to enter the cylidners, which in turn causes a missfire at idle.


Honda does not supply a diagnostic flow chart for this code. P1399 is a random misfire code and Honda/Acura has reported for various models that this could be caused by clogged EGR ports. In addition there is the possibility that the valve cleareance specification may be out of range.


Customer: replied 9 years ago.
Reply to RIP's Post: mis-fire over full RPM range. i would think that it would clear up at speed as the EGR would be open to some degree depending on driving conditions. The EGR was replaced under warranty at ~45K miles
Expert:  RIP replied 9 years ago.

To have a misfire across all the cylinders it can only be fuel related, computer injector control, cam timing, vacuum leak, or the EGR system...not ignition related since each cylinder has it's own ignition coil. The EGR system by far is more the reason for all these misfires at 130k, where as engine and fuel system problems are less likely. If the EGR valve was replaced at 45k miles,,,that's almost 100k miles the chances for another bad valve are great. But if the intake manifold has not been cleared through ever, this poses even more of a concern. Also, the EGR system is set to operate after the car has reached normal operating, if the ambient temps are colder it will take longer for the engine to get hot enough to accept EGR gases, so it is possible to feel an EGR misfire in gear, at speed...


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Customer: replied 9 years ago.
EGR valve clean (could not see light through valve seal. EGR port at valve interface had very minor build up.

Added 1 can Heat (fuel dryer) and drove car ~10miles. No change. IML flashing indicating potential for converter damage.

Ran cold engine compression test this morning. Low = 192psi high = 200psi. All plugs look picture perfect.

Going to put frsh plugs in later this morning to see if there might be a hidden defect like a cracked insulator.
Expert:  RIP replied 9 years ago.

Don't replace the plugs would be rare that all the plugs would cause this. Check for any vacuum leaks around the intake with carb cleaner, and around the base of the valve. Remove the EGR valve and see if the engine will run with the valve removed...if so, than the intake is plugged. With the valve out, put some carb cleaner down the port and see if it comes out of the pintle, even the smallest amount...if so the valve is bad...

Let's check these items first, before we did into the fuel system.


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Customer: replied 9 years ago.
Removed EGR and filled port with carb cleaner - nothing seeped thru the pintle. Did same from pintle side - cleaning fluid level remained same for >1 minute.

Ran engine with EGR valve removed. Assume exhaust side clear based on noise level. Mis-fire remained with intake side of EGR manifold open or blocked off.

Sprayed carb cleaner around intake and vacuum hoses - no affect in mis-fire

OBD codes remain same

Coolant and oil look normal (no foam or froth) which should rule our head gasket.

I did fill up at a gas station I've never used before. The car was parked in garage within 10 minutes after the fill-up and sat unusde for 1.5 days. My daughter was 1st to drive it and said it started running poorly after about 2-3 miles of driving.

I feel I should tell you that I was an NIASE certified mechanic (NIASE preceded ASE) up until I changed career paths in 1981. I try to do all repairs but it's certainly getting more difficult to diagnose problems. This is my 12th Honda vehicle. I've had recurring water-in-gas problems with 2 different Civics - have always lived in cold winter climates. One Civic was carburated and one was injected. The rough idle and mis-fire of this vehicle reminds me of the water-in-gas episodes.

Unless you have another path to explore I'm taking the Accord to a Honda dealer Monday am.

Thanks for your assistance.
Expert:  RIP replied 9 years ago.

Did the engine run with the EGR valve off? Have you removed the fuel filter out and poured out the gas in a clear container? Your theory on "bad gas" may be true here.


Customer: replied 9 years ago.
The engine ran but worse than with the EGR valve in place. I ran it for only a few seconds as I live in an aparment complex and we're not supposed to perform vehicle repairs on site.

Because of the no vehicle repair rule I tend not to perform any work that might result in any strong fumes or odors. The car is at the dealer waiting in the service queue. I provided them with very detailed info and placed emphasis on the bad gas theory. I'll let you know the outcome.

Just out of curiousity have you ever experienced a gasoline powered vehicle filled with 25% gas and 75% diesel fuel? I know I put mid-grade gasoline in but what if the tanks were incorectly filled.

Expert:  RIP replied 9 years ago.

Yes, if Diesel was put in the engine would not run. Not even with 25% Diesel. It might run with very little Diesel and ping with no power. It sounds like you may end up with water in the fuel, bad gas, or still possibly the EGR system malfunctioning. Let me knoif you have any questions after they take a look at it.


Customer: replied 9 years ago.
Honda tech finally arrived at "bad gas" diagnosis. tank was pumped out, 2 gallons of fresh gas added and what do you know...the engine problem was resolved. Well almost. A post "new-gas" scan indicated there was still a mild & random misfire in Cyl. #2. A new coild fixed that problem. The vehicle is running as perfectly as it did before the problem developed.

They service manager said the gas had a strong alcohol odor. i told him I added a can of dry gas to 3/4 tank. He said the odor was much strger than you'd expect from a single can that had been mixed with the gas for a few days.

My next task is to approach the 7-11 store about the situation as the total cost came to $434.19 including the coil, oil & filter and fresh gas. I wish i could have drained the tank myself!!!

One more thing - after I filled the tank the check engine light came on. I hurried back to the dealer but the mechcanics had left for the day. I ran a scan at home and got P1491 EGR Insufficient Lift. A quick check under the hood found the EGR harness connector laying next toi the valve. Plugged it in, reset the code and have had at least 3 restart/trips with no additional problem.

Called the dealer this morning to complain about the obvious lack of test drive time they put in after the repair. MI v MO was only 1 mile. Not enoiugh time for the engine temp to come up to where the EGR valve is activated.

Thanks again for your help.
Expert:  RIP replied 9 years ago.


You did an awesome job and it sucks that places can still not take care of their underground tanks and allow customers to get bad fuel. Imagine all the other people who fueled up their the last few days and are having the same problems as you. At least you know that because the dealer and us came up with the same conclusion, that you didn't get ripped off on any repairs. As for the test drive, I don't know why most technicians don't put the adequate mileage on the vehicle's, Aviation technicians don't let the planes out with passengers until extensive testing after repairs, should we do the same?? Great job on everything, let me know if you ever run into any trouble I can add my advice to :)


Customer: replied 9 years ago.
When I was working as a mechanic I always invested time in a test drive mainly because you wanted to ensure the repair was complete but also to see if there were any other drivability or handling issues that needed attention. This wasn't meant to pad our pockets but more to build a solid relationship with our customers. As much as ten years after I changed career paths I would get phone calls at home from an old customer wondering if I had a change of heart and gottent back into the business. I guess the real capper is that I married one of my customers - she had a 1976 Civic CVCC standard transmission. I put custom wheels and tires and a Momo steering wheel on that car for our 1-year anniversary. That was 12 Honda cars, 2 Honda motorcycles (CB750's) and 1 Honda lawnmower ago. And she's remained a loyal "customer" of mine for 29 years.
Expert:  RIP replied 9 years ago.