Intermittent p0305, only when cold.

[Daemoro]

OK I did several searches for this and couldn't find anything similar. Several "when up to temp" threads but nothing quite like this. So apologies in advance if my search-fu is weak.

2005 v8

Last winter when the temp dropped well below freezing I had a problem crop up with a misfire on start up. My daughter (17 years old actually listened to me!) turned the truck off, called me and said it was running rough and the check engine light came on with the three traction control lights. I brought my code reader and it showed P0305. I let it warm up at idle. Cleared the codes and started it again. It was fine. No misses no running rough.

Same problem happened twice more when it was cold out. But it went away once the truck was warmed up.

Fast forward through all the warm weather to last week. Yeah I put off checking out the problem and forgot about it... I'm an idiot. Below freezing again and the miss starts while I'm driving but goes away and comes back a few times until I get where I was headed. Started the truck half an hour later. The engine was still warmish and no problems going back home. Checked the pending codes P0305 again.

Today my intentions were to swap the #5 coil pack with the #1 hoping it would get cold enough to see if the problem moved with the coil.

I took #5 out and the shaft of the pack looked like it had surface rust or at least rust colored dirt all over it.... you know, since plastic doesn't rust. Being a keen investigator I thought: "That's not supposed to look like that."
But to be sure I pulled #1 anyway and sure enough it was a nice clean gray plastic... looked like new really.

So I'm thinking some moisture got past the seal at the top and created an arc between the coil and the head somewhere causing the misfire. Once the truck got warm the moisture evaporated? No more moisture but the damage is probably done to the coil and now it's "going bad" but hasn't completely crapped out yet.

My plan is to buy a new coil pack and a plug for #5. If I get it sealed properly it should prevent any moisture problems in the future and I feel pretty confident that this will fix my problem.

Any advice on or experience with things up to this point would be appreciated.

My other concern (other than is swapping the coil and plug going to fix it?) is... how the hell do I clean out the rust/dirt crud in the shaft that leads down to the plug? I'm assuming soapy water is probably a bad idea. Getting anything down in there that will fall into the cylinder once I take out the plug probably belongs in the BAD column. What do I do? Do I just not clean it out and hope for the best? That doesn't sound like a viable solution.

Little help?

 

[AuSeeker]

OK I did several searches for this and couldn't find anything similar. Several "when up to temp" threads but nothing quite like this. So apologies in advance if my search-fu is weak.

2005 v8

Last winter when the temp dropped well below freezing I had a problem crop up with a misfire on start up. My daughter (17 years old actually listened to me!) turned the truck off, called me and said it was running rough and the check engine light came on with the three traction control lights. I brought my code reader and it showed P0305. I let it warm up at idle. Cleared the codes and started it again. It was fine. No misses no running rough.

Same problem happened twice more when it was cold out. But it went away once the truck was warmed up.

Fast forward through all the warm weather to last week. Yeah I put off checking out the problem and forgot about it... I'm an idiot. Below freezing again and the miss starts while I'm driving but goes away and comes back a few times until I get where I was headed. Started the truck half an hour later. The engine was still warmish and no problems going back home. Checked the pending codes P0305 again.

Today my intentions were to swap the #5 coil pack with the #1 hoping it would get cold enough to see if the problem moved with the coil.

I took #5 out and the shaft of the pack looked like it had surface rust or at least rust colored dirt all over it.... you know, since plastic doesn't rust. Being a keen investigator I thought: "That's not supposed to look like that."
But to be sure I pulled #1 anyway and sure enough it was a nice clean gray plastic... looked like new really.

So I'm thinking some moisture got past the seal at the top and created an arc between the coil and the head somewhere causing the misfire. Once the truck got warm the moisture evaporated? No more moisture but the damage is probably done to the coil and now it's "going bad" but hasn't completely crapped out yet.

My plan is to buy a new coil pack and a plug for #5. If I get it sealed properly it should prevent any moisture problems in the future and I feel pretty confident that this will fix my problem.

Any advice on or experience with things up to this point would be appreciated.

My other concern (other than is swapping the coil and plug going to fix it?) is... how the hell do I clean out the rust/dirt crud in the shaft that leads down to the plug? I'm assuming soapy water is probably a bad idea. Getting anything down in there that will fall into the cylinder once I take out the plug probably belongs in the BAD column. What do I do? Do I just not clean it out and hope for the best? That doesn't sound like a viable solution.

Little help?

I believe that your issue is more to do with the connector in the coil pack is worn and when it's cold the contact is even less soild, or more likely there a crack in the coil plastic around the connector, the residue your seeing is from arching and that is causing the misfire, replacing the coil pack should solve the issue.

Don't remove the old spark plug before attempting to clean out the coil/spark plug hole, use compressed air with a blow nozzle that has a long tube on it so you can blow air from the bottom and thusly any debri will blow up and out of the hole, doing this and also using a thin plastic "bottle" brush will help to scrub any stuck on debri loose, repeat until you think it's clean enough, then slightly break loose the old spark plug and then use the air nozzle again to blast any carbon buildup/debri out of the hole, (I do this step everytime when replacing my plugs so no loose carbon buildup/debri falls into the cylinder), if you don't have a compressor and blow nozzle you can buy cans of compressed air that come with a plastic straw typically used for cleaning dust inside of computers and electronics, get at least 2 or more cans to ensure you have enough, if you don't use them all they come in handy for when you're cleaning the interior of your vehicle or anywhere you need to clean out debri/dirt/dust, etc. in tight places.

 

[Daemoro]

Thanks for the tips. I was thinking about getting a small air compressor anyway and I happen to have a $25 Lowes gift card so.... looks like I will have that air compressor tomorrow. Maybe I can knock one off the shelf and move it over to the scratch and dent area.:jk: