The dreaded misfire

[Seafury]

Hello again.

So since its gotten ridiculous cold here in VA my 98 V6 has been misfiring on cylinder #3.
We (me and my mechanics at NTB) sprayed water on the coils and saw #3 arching to the block.
Last week I pulled the coil-pack and boot and crammed everything with dielectric grease.
The stuttering went away, then yesterday I went to go to work and it was back in a BIG way. ......
Instead of just at idle it was now stuttering all through the rpm range and otw home last night
I even got the check engine light flashing and then solid on.
Before I had no codes. A scan after I got home showed misfire on cylinder #3 hmmm.....


So today I swapped coil/boot from #3 to #1 cylinder all the sudden the engine is running fine all day today lol.


The phantom misfire strikes and runs away to fight another day!

 

[Grenvilleter]

Haha...good for you but don't take any odds that it won't show up again.

When an arc occurs, it leaves a carbon trace thus reducing the effectiveness of the dielectric to insulate resulting in a repeat performance when conditions are right eg: damp or wet conditions or even high humidity.

At least you have a little breathing room to source out a replacement and probably won't take long to diagnose the next time around.

 

[Ex-ToyTech]

Also possible the #3 injector is going bad. Been down that road a couple of times. :wink2:


Tim

 

[Srabai]

Seems like a new coil pack and some wires might give you some peace of mind. Hopefully it's nothing serious.

 

[the great him]

how many miles on the truck? the coil packs usually start seeing issues around 300k on them, some will last longer, some go sooner. to me it sounds like you have a bad coil pack. the dielectric grease is only a bandaid fix. also when was the last time you replaced your plugs and wires?

i doubt youd have an injector issue, as that would read out in other places such as o2 codes for too lean ect.

 

[LittleCaesar]

NTB - National Tire and Battery guys?

Start with the wires and plugs as others have suggested.

 

[Seafury]

Thanks for all the thoughts.

Yes I am a service manager at National Tire and Battery.
I did plugs and wires and 1 coil boot and dielectric grease last summer.

I am hoping it is a coil, only because its easier to change than an injector lol.

When you fix other people's cars for a living 12 hours a day its hard to find time, energy for your own heh.

 

[Ex-ToyTech]

Should have clarified my answer a bit. If your misfire code comes back on #3, I would look at the injector. If the misfire moves to the other cylinder, then you're golden. :biggrin1:

...

i doubt youd have an injector issue, as that would read out in other places such as o2 codes for too lean ect.

Fixed a bunch that only had a misfire code (not just on 3.4s either). :wink2:


Tim