[mikehumphreys80]

So I have a 2011 touring, 175000kms on it. Been having some issues recently with the car starting to run rough and through the misfire codes, while this happens the check emission system light comes on, the VSA warning light and the check engine light flash. After turning the car off and back on the check engine light is gone but the other 2 stay and the codes are stored. I'm getting codes p0300, p0304, p0305, p0306. I took it into the dealership a week ago hoping I may fall under the warranty extension for the piston rings and such. The plugs hadn't been changed while I've owned the van(2 years) so they said that would have to be done before going any further with a warranty claim. So I've now changed the plugs and cleared all the codes and just yesterday it happened again. Any thoughts or ideas? the warranty extension only is for cylinders 1 through 4 so whatever is happening with 5 and 6 would have to be something I pay to have fixed i'm assuming. Thanks

 

[Navar]

Based on your description, I would guess that something else is going on here (other than the 'typical' Cyl 1-3/4 failure) - so yeah, you are likely going to have to pay for it.

While that's not enough info to diagnose the problem, there are a variety of things which could cause 'random' or 'multiple' misfires indicated by the P0300. If you are consistently only getting P0300, P0304, P0305, and P0306, it seems possible that only Bank2 is being affected.

I suspect that whatever's going on has also fouled the cat - so there's that.

You'll need to do some more diagnostics to try to determine the source of the problem. First I'd pull those new plugs and inspect. Their condition (since they are brand new) could be a strong indicator. What did the old plugs look like?

I wonder... Have you replaced the TB recently? Have you done it yet? (possibly the cam is off by a tooth, or slipped?) doesn't sound likely I know, just a thought of things that would only affect Bank2.

 

[egads]

I do think your issue has to do with the “experimental” low friction piston rings Honda used in your model year. What the dealer is telling you is that you are due for spark plugs. Has the timing belt been replaced? How many km was on it when you bought it? Do you have any service history?

FYI for those of us in the US, 170,000 km is 108,740 miles.

 

[mikehumphreys80]

Timing belt was done 6 months ago or so. Spark plugs done just last weekend. I didn't have the valves checked. I think I'm going to have the shop that did my timing belt check the timing and verify that it's ok. My dad and I did disconnect each coil one at a time while the car was idling to see if they were all functioning and they all seemed to cause a difference in the idle. Is there anything that controls bank 2? Cylinders 4,5,6?

Based on your description, I would guess that something else is going on here (other than the 'typical' Cyl 1-3/4 failure) - so yeah, you are likely going to have to pay for it.

While that's not enough info to diagnose the problem, there are a variety of things which could cause 'random' or 'multiple' misfires indicated by the P0300. If you are consistently only getting P0300, P0304, P0305, and P0306, it seems possible that only Bank2 is being affected.

I suspect that whatever's going on has also fouled the cat - so there's that.

You'll need to do some more diagnostics to try to determine the source of the problem. First I'd pull those new plugs and inspect. Their condition (since they are brand new) could be a strong indicator. What did the old plugs look like?

I wonder... Have you replaced the TB recently? Have you done it yet? (possibly the cam is off by a tooth, or slipped?) doesn't sound likely I know, just a thought of things that would only affect Bank2.

 

[mikehumphreys80]

The misfires are also random. Like I can go a week or 2 inbetween it happening also.

 

[Navar]

As far as I am aware, there is no specific electronic control for just Bank 2 ... which was why I asked about TB... though if reasonably recently done, and done properly, It's not likely something like the mechanical timing is causing Bank2 to start misfiring...

I would def check/adjust the valve clearance... also inspect the cam.. not likely a problem, but something is causing Bank2 to random misfire at random intervals, and hypothetically, the valves could be causing this... luckily Bank2 is the forward bank, so easier to mechanically access...

I would also do a compression/leakdown test on bank 2 before and after you've checked/adjusted the valves...

I wonder...

Does it only occur while VCM is active (ECO light on...)? or during the switch on/off of VCM? ... might be hard to determine if so, as you, are, you know, driving at the time....

Obv. I'm just spitballing, but I'm struggling to think of something not mechanical... nothing pops into my mind...

 

[egads]

Did you use the factory spec plugs? They are really expensive, but the only thing you can use.