[Elliotthd]

Good morning everyone. I have a 2013 C5 Classic. It has a Nfieldgear EFI Muffler, K&N Air Filter, and a recently installed PCV. Since installing the PCV the bike has been running wonderfully, and I've been enjoying the back roads and sides streets more than ever.

Now for the head scratcher part. Last night I had to take a short trip from Philadelphia PA to Wilmington DE and i was in a hurry, so I-95 was the road of choice. This was the 1st time I've been on the highway since I installed the PCV. As I was cruising at around 65mph on the clock, I kept having an intermittent miss. Like a quick stall out every so often. Same thing on the ride home. Cruising along at 65, then miss, cruise along, miss. I tried slowing down to 55, same issue, then I punched up to 75 and same issue. I thought maybe it was the plug, but upon inspection when I got home, it looked perfectly healthy.

I rode to work today and had no issues or miss fires, but my ride to work is stop sign to stop sign, so I never get out of 3rd gear. Anyone have any ideas why I'm getting miss fires, or at least what feels like miss fires, at sustained cruising speeds?

[NField Gearman]

I'd check the MIL system for a code.  It's likely that it's not related to the power commander at all and something else entirely.

[Elliotthd]

I'll check it, but the Dummy Light isn't on.

Also, I left this part out, I did reach down and push the plug wire down on the plug while riding, just to make sure it hadn't come loose, that did not fix the issue.

[Elliotthd]

I've got no codes.

[John20121978]

My 2012 c5 is doing the same thing. No codes either.

[High On Octane]

I would be taking a look at the negative battery cable.  They are known for breaking under the insulation and causing random misfires.

[Elliotthd]

Yeah, I've fixed mine maybe 15 times now. It just a bad design. I guess I'll check it again. That hadn't occurred to me, since the most recent fix seemed to be holding when I installed the power commander.

[Elliotthd]

Everything looks intact here, though being at work, I can't tear it apart and really inspect it. I'll have to check it out when I get home and see if maybe the cable end is loose on the wire. I have a feeling that you're correct about this Mr. Octane.

[gashousegorilla]

Good morning everyone. I have a 2013 C5 Classic. It has a Nfieldgear EFI Muffler, K&N Air Filter, and a recently installed PCV. Since installing the PCV the bike has been running wonderfully, and I've been enjoying the back roads and sides streets more than ever.

Now for the head scratcher part. Last night I had to take a short trip from Philadelphia PA to Wilmington DE and i was in a hurry, so I-95 was the road of choice. This was the 1st time I've been on the highway since I installed the PCV. As I was cruising at around 65mph on the clock, I kept having an intermittent miss. Like a quick stall out every so often. Same thing on the ride home. Cruising along at 65, then miss, cruise along, miss. I tried slowing down to 55, same issue, then I punched up to 75 and same issue. I thought maybe it was the plug, but upon inspection when I got home, it looked perfectly healthy.

I rode to work today and had no issues or miss fires, but my ride to work is stop sign to stop sign, so I never get out of 3rd gear. Anyone have any ideas why I'm getting miss fires, or at least what feels like miss fires, at sustained cruising speeds?

  Interesting. It's not the first time I have heard that .  I would check your map and make sure it is the one for your bike. You can also try unplugging the PC-V , put it back to stock . Then see if the problem goes away at high speed/ high revs.

[cstorckiii]

I put my PCV on in November, and was having the same issue. For unrelated reasons, I spent the last month tearing down and rebuilding my engine. I also took the opertunity to decarbonize the head, piston, and cylinder. I've had the bike back on the road since Friday, and it has been running flawlessly. You may have enough carbon on your piston crown to create a slight over rich condition. GHG, am I thinking in the right direction?

[Elliotthd]

Ugh, don't tell me that. I didn't expect to have to tear this motor down for any reason at all for like 30,000 miles. I'm gonna pray that it's the negative battery cable for the 100th time in 2 years and go from there.

[johno]

What grade and manufacture of spark plug are you using?
This may simply be an overheating plug issue........

[gashousegorilla]

I put my PCV on in November, and was having the same issue. For unrelated reasons, I spent the last month tearing down and rebuilding my engine. I also took the opertunity to decarbonize the head, piston, and cylinder. I've had the bike back on the road since Friday, and it has been running flawlessly. You may have enough carbon on your piston crown to create a slight over rich condition. GHG, am I thinking in the right direction?

  I think you might be. And I hear ya about the possible condition of the chamber  BEFORE the PC-V is installed.  I have seen some pretty badly carbonized chambers and piston crowns... leaking valves and such. But , that may have to do with the very low compression and possible leaks at the exhaust port/ header connection. At least as far as carbon goes.   But.... Where I heard about this issue before. There was not a lot of miles on the motor. So I'm, not sure.   

And I wouldn't make the Jump to that yet.. although you may be right.  I think the simple first step would be to plug that PC-V into a laptop or PC. Make sure the right map for the bike is running.  And/or also simply unplugging it and see if the problems goes away.

[NField Gearman]

Could also be the sidestand switch.  Those like to make it sputter at higher revs.

[Vince]

     Yes to checking the negative battery terminal and the side stand switch.
      Also, change the spark plug. The stock Bosch is really not that good. The NGK BPR6ES is MUCH better. No matter what plug you use,  mostly going at low speeds/low RPM will foul it. It may look OK, but there can be enough of a baked on coating to inhibit spark. It is a cheap and easy check that fixes most of these types of complaints.
     There is also a possibility of some water in the gas. Over night a half filled tank can have enough condensation to seriously impede running. Dump in one ounce per gallon of gas of any product the "Cleans your fuel system as you drive" or "Removes water". They all work the same way. The chemicals break down the surface tension of the water so it can mix with the gas and pass through the jets or FI orifices. Untreated water is too dense to pass through the same small holes as gas, so it will block off fuel flow.