I have a 2000 Honda Accord EX 4 Door 3.0 V6 with 111K miles. At 108K miles the timing belt, water pump, spark plugs, air filter, and drive belt was replaced at the Honda Dealer by the previous owner. Recently on two different occasions in the same day a few hours apart the car idled rough when started. I had to keep patting the gas to keep it running. After a few minutes it ran fine. It seemed only to run rough at idle on startup.The CIL came on and when I scanned it there were missfires on all 6 cylinders. The codes were P0301, P0302, P0303, P0304, P0305, P0306, P0300, P1399.

I reset the CIL and have driven the car the last several days without any problems. The car has been running great. The only thing I did was buy a can of Sea Foam gas treatment and filled up the tank with fresh gas. The car has sat quite a bit in the garage over the winter but I did start it once a week and let it run for about 5 minutes to keep the battery charged. Any help/advice from anybody that has had this similar problem is appreciated.

 

I could not find a code 1399. Recheck codes and post them.

Closest code 13nn ending in 9 was 1359, disconnected TDC/CPS/CYP sensor.

good luck

 

These are the codes:

P1399 - Random cylinder missfire detected

P0300 - Cylinder missfire detected - random cylinders

P0301 - Cylinder #1 missfire detected

P0302 - Cylinder #2 missfire detected

P0303 - Cylinder #3 missfire detected

P0304 - Cylinder #4 missfire detected

P0305 - Cylinder #5 missfire detected

P0306 - Cylinder #6 missfire detected


I drove the car again today and it started and ran great. I've heard of other 2000 Honda Accord 3.0 V-6 owners that have had this same exact problem. I've heard of several possible causes but I'm not sure if any of these pertain to my engine:

1. Clogged fuel inj/ bad fuel

2. Bad coil

3. Bad spark plugs

4. Vaccum leak

5. Bad idle air control valve

6. Clogged fuel filter, Bad fuel pressure regulator, bad fuel pump

7. Bad throttle body sensor/ bad throttle body

I called Honda Customer Service and no warranty work has ever been done on this car. Only routine maintenance. I don't want to buy parts I don't need. As of now the car has been running great but I've heard this can be a intermittent problem that occurs with 2000 Honda Accords with the 3.0 V-6. Any technical advice would be greatly appreciated Texas Honda.

 

I had 2 different people scan the codes and they are the ones I posted. One guy worked at AutoZone and the other guy was a independent mechanic. Neither seemed to know what the problem was since it was running great at the time they checked the codes. The independent mechanic said to use the Sea Foam fuel treatment just in case it should have some bad fuel or a possible clogged fuel injector. He said to drive it everyday and see if it happens again. So far it hasn't happened again. I want the car to be dependable because I'm giving it to my 16 year old son to drive.

 

I checked two websites, batauto and autozone and neither had a code P1399 listed for Hondas of your vintage. So somewhat of a mystery why you're showing a apparently non-existent code. I checked for others w/ this code and it does appear fairly frequently in Obd2 Hondas. Perhaps it's a non-documented code.

You have missing on all cylinders. The common things likely to cause missing in all cylinders are 1) distributor rotor, ignitor, and coil. Of these coil seems most likely, perhaps an intermittent short in the secondary that weakens the spark to point of missing. A cracked rotor might cause this problem, but unlikely to be so infrequent and random, usually will cause all the time miss.

Fuel problems are unlikely in my experience. If you have adequate fuel pressure, you're good to go. I've never seen a well documented case of low fuel pressure, but it may occur. Also the long intervals of good performance do not align w/ a fuel delivery problem. Six bad injectors can be ruled out IMO.

Bottom line is this will be difficult to diagnose since it's very intermittent. Two options are available; start replacing parts and hope the problem is addressed, or wait for things to get worse to allow diagnosis.

I would suspect that your problem is the reason the car was sold. This type of problem causes ordinary folks to throw in the towel quickly.

Perserverance is the coin of the realm. If it were mine, I would drive myself for a while and wait for additional clues to appear.

good luck

good luck

 

Thanks for the information. I will keep driving it to see if the problem occurs again. If it does I will take it to a Honda technician that can diagnose the problem without hopefully replacing unneeded parts. I hate to guess and replace parts I don't need. That can get expensive and frustrating. I appreciate you taking the time to help me. Thanks again!

 

P1399 is listed in the Helm book (I had a 98-99 Helm book but not the V-6). In the code list it doesn't get its own separate "line item" but it's listed as a secondary code that appears along with the misfire codes.
P0301 (71) cyl.1 misfire (P1399)
P0302 (72) cyl.2 misfire (P1399)
P0303 (73) cyl.3 misfire (P1399)
P0304 (74) cyl.4 misfire (P1399)

So P1399 doesn't really mean anything new beyond the misfires.

 

Thanks Jim, it may be a code like P0700, a trans code that seems to appear whenever any other P07nn code is presented.

regards

 

P1399: "Misfire in any cylinder"

 

Page, I'm wondering if you've had any luck figuring out your problem. I've got the same P1399 code and intermittent idle problem.