Hey there,

So my MY02 has been idling rough about 2 mins into each cold start. It does the puffing (sounds like phub phub ...........phub.......phub phub phub) from the exhaust that i have read about. Im pretty sure its a misfire. It is only on cold starts and goes away once i start driving. Once its warmed up i do not think ive heard it nor do i experience any hesitation, vtec seems fine.

I get code P1399 every couple days but no CEL. I finally did catch a steady CEL this week and it was codes P0301 and P0303. Ive reset them after reading the codes and it was fine until P0303 showed up a couple days later but has yet to come on again. All codes ive ever seen where after letting the car warm up while i have a 5min smoke break. None have every come up while moving.

I have done the following

-Replaced Map

-Replaced spark plugs with OEM ones from Honda. Double checked that its tightened to 18lbs.

-Tried Fuel Injection cleaner

-Reset ECU (after ecu relearns its the same symptoms)


Everything that ive read suggest that its a bad coil or dirty injectors. I have an appt at Larry Hopkins Honda to do a valve adjustment but would that cause the cold start issue? The car has about 80,xxx miles on it.


Any inputs?

Thanks

 

I would love to know the answer to this also, mine started doing this right before I put it away for the winter. But yea, same puffing sound as you described.

 

I am leaning towards a bad coil. If you are getting misfires and you do in fact have brand new OEM plugs (which are NGK PFR7G-11S), then I would think a coil is the culprit.

Have you had a leakdown test done?

 

If you suspect the coils, switch the coilpacks around, while keeping track of which is which, and see if the misfire follows a particular pack.

 

Hey there. I think i have solved the cold start issue.

I ended up replacing the coils, its been about 2 days since i swapped them out. My cold start idle is now what id expect it to be, there is no more plub plub puffing either.

I think i had 2 coils possibly going bad, i mentioned the 301 and 303 codes previously but it only happened on cold starts and must have been so light that it rarely threw a code.

I also got the valve adjustment done. It wasn't the cause of the puffing but at 8x,xxx miles, i was told they were loose. Thanks itS2Krazy. Great job, the car was smoother and quieter after.

 

Thanks OP this thread has been a great help for me.
I had the same symptom, misfire when the vehicle is cold.
My AFR read the engine was running lean when misfire happened.
Coil pack was the problem. With those replaced, the car has been fine fore a week.

Jay

 

Sound like this?

https://www.youtube.com/watch?v=4CyvOwUtuyw