08 OB with 105K. I get P0303 when car has been sitting in garage and humidity is off the charts.

Runs like crap then after sitting out in the sun (drying out) engine smooths out and code disappears after drive cycles.

Wires or coil? 

Edited July 11, 20205 yr by brus brother

Probably wire,

Switch to another cylinder, clear code and see if code returns on the new cylinder.

O.

ok got 1 and 3 off. 3 had moisture down around the wire tube. Dried it off and put back together. Is there anything I can spray/lather on the boots to prevent the moisture from seeping down along the tube?

 

Edited July 11, 20205 yr by brus brother

DOW Corning 111 valve sealant. 

GD

thanks for the tip GD. I assume you apply it to the outer lip of the plug wire as shown below at the widest point of contour? Or do you slather it over everything from the front bumper back to the A pillar;-)?

Edited July 12, 20205 yr by brus brother

Yes. It's also nice on toast.

GD

spoke too soon. misfire and code returned. pulled plug and sure enough, 'twas oil on the tube and not condensation.

will need to change VC gaskets and grommets?

P0303 is Baaaack!

I swapped cylinder 1 and 3 wires a few months ago but the code doesn't follow the wires.

Still showing cylinder #3.

Was pretty cool and rainy around here for a few days then popped over 90 today. The garage was dripping with condensation. Ran rough until I opened the hood outdoors and let the humidity settle down.

Coil?

If coil it is, any opinions on decent aftermarket or any ole one'll do?

 

Edited June 6, 20214 yr by brus brother

try running it when dark out.. pop the hood, start the car, and look for arcing.

can be done at anytime... humid or not.. just use a spay bottle to mist moisture over the coil area.. if it is the coil, you will see it

sometimes the arcing is bad enough, it doesn't even need to be dark out lol

this was on my 95 Legacy... https://youtu.be/jMNfF-vcUDs

 

 

Any silicone dielectric goo (that's a term of art) will do, and use it liberally at both ends of the wire after cleaning everthing up - once the arc starts, it creates carbon tracks that it likes to continue to follow, especially on the surface of the (ceramic) plug insulator.  If it still acts flaky and the fault sticks with the cylinder, you may have a hairline crack in the insulator, so you're just going to have to replace the plug.

Edited June 6, 20214 yr by jonathan909

1 hour ago, heartless said:

this was on my 95 Legacy... https://youtu.be/jMNfF-vcUDs

Ooooo!  Pretty light show!

1 hour ago, jonathan909 said:

Ooooo!  Pretty light show!

yes, it definitely was and in broad daylight, too! LOL

just goes to show how bad it really was

 

Wow, that video would seem to indicate that you might get codes reading adjacent cylinders.

any thoughts of oem or aftermarket (specify brand if you like) for a replacement?

as I said I have already swapped wires and the code fault stayed with the cylinder so the wires would seem to be OK.

honestly, that situation is not real common, so I would go with a used OEM one matching your year, or close to it. that was what I did - grabbed the coil pak off my old 1990 Legacy and plopped it in.. no more problems

and yeah, you would think it would show more than one misfire code, but it only ever threw the one cylinder, and it was always when it was damp out.