its been a long time since i have been here, but im back bc this place was my home when i still had my accord and always helped me when i needed it.

so my cousin has a 99 coupe v6, and said it just started misfiring on all cylinders.

he took it to autozone and it was throwing multiple misfire code.

he changed his cat bc they told him to, still does it.

i am going to help him tomorrow, but figured i would come here and get a few ideas on where to start.

i was gonna start with plugs, test coils, test fuel pressure

anything that messes up that causes the J30 to just misfire out of nowhere?

 

EGR port in the intake manifold gets clogged, there is a TSB floating around on it......but start with the normal stuff to rule those out.

 

And I think the 99 still had a cap and rotor set up....the COP didn't start on the v6 until 2000 but my memory is REALLY bad.

 

okay, thanks man! hope the egr ports are easy to get to on the v6's

was a piece of cake with my f22

 

I went and looked. The 99 V6 still uses a distributor. COP didn't start on the v6 until 2000. So the cap, rotor and wires are in play as well.

 

The v6 port is a bit different than f22. The intake has to come off. The TSB I referenced was for an "update" to the port in the intake.....something with drilling the hole/port to a larger size and inserting a sleeve of sorts.

 

think dealership would do this for free?

 

Multiple misfire codes may also be caused by an EGR valve that is stuck open when it should be closed (see attached pic. info.)

The EGR port clogging issue warranty extension was 8 years or 80,000 miles, which would essentially be over. Honda TSB 99-085

 

ended up being a bad coil. it was actually a 2000 model with the COP ignition.

threw in a new set of ngk iridium plugs and replaced the coil.


used my torque app to monitor rpm drop when unplugging coils. no rpm drop on cylinder 3. swapped coils around and bam, same thing. bought new oem coil.

runs like a champ again. 44.95 for coil and 40 for plugs. not too bad.

it was throwing P1399 for random multi misfire.

 

Cool....

Thanks for coming back....you know you can stop by and help anytime you want.