04 Verona Runs Rough in Wet Weather

[a1aman]

Hello, I have an 04 Verona with 57k miles that recently started to misfire and run rough on very rainy days only. Dry weather it's fine. The mechanic said the codes read the ignition coils on 2 and 3 were showing a problem so they were changed out. By the way, his quote for the coil costs were over twice what can be gotten on the web. I didn't think I could do the job myself having no experience with this type of ignition. Well it's still doing it. Do the other coils have to be replaced and is it a fairly easy job, or is there something else that this car is prone to that is going on? Jerry

[Glenngeb]

Had the same issue with an '05 and found the spark plug boots to be full of carbon causing a short when damp. I would get after market boots and go to a good mechanic and not the dealer as they will charge twice as much for both the parts and the labor.

[ewetho]

The Verona suffers from the the insulation shrinking and cracking on the injector and coil harness. Look for exposed wire on the wires to the injectors and coils.

If that is the case the intake has to come off to service.

Would explain wet weather issues.

Occasionally you can get oil leaking into the sparkplug tubes but should have been found if the coils were replaced.

Also 30K interval on sparkplugs.

[francois]

I own an Epica 04. Engine was running rough in any weather, with frequent Check Engine light on. Eventually found one dealer who had the answer: The main wire harness was replaced. That worked well.

[a1aman]

The harness looks ok besides the usual road grime, though it doesn't appear to be particularly robust. I think I will go with changing the spark plugs and a good inspection of the remaining coil packs that hadn't been changed out since only two were replaced.Hopefully that cures the problem. If not, I'll try replacing the remaining packs. I couldn't find the ignition wire harness online, I'm trying to avoid going to he dealer or getting the parts through my mechanic since there is always the huge mark-up. Thanks for the posts.

[bootlegger1063]

I agree with the poser that said the main harness. These vehicles are notorious for substandard materials and workmanship. I used to work for Corporate and what I found to be effective is a compound called Stabilant 22. I purchaced it at Carquest, but most MAJOR auto parts stores can get it. It is pricey(about $80 for a visine sized bottle) but a little goes a long way!!! Brush it on the connectors at the coils and main harness connectors. It enhances the conductivity of the cheap connectors Daewoo uses. I have fixed a lot of GM-DAT products using this stuff and it really does work!! Follow directions and that bottle will last for a good long time. Good Luck!