2004 CV Engine Misfire in Snow

[Dan07]

I have a 2004 CV with 105K miles. The engine intermittently misses when it is snowing. There is never a problem in rain or on wet/snow covered roads only while it is snowing. The car has been doing this for about two years. No trouble code ever. My guess is a bad coil but I have no way to determine which one since the problem is sporatic.

Last week on the Indiana toll road, it missed about once every 10 minutes in heavy snow. I goosed the throttle to try to get the miss to stop and almost spun 180 degrees. Any idea why the engine is missing in snowy weather? I changed the plugs and all filters at 100K but the problem did not go away.

[mark v]

Time you change your Spark Plug Wires, they are bad. What is happening is the wires are getting wet when the snow and slush hits them and are shorting out. Pop your hood at night, start the car and look at the wires and you might see sparks jumping too, you can also spray water on the wires at night when it is running and see the sparks arc.

[Dan07]

Thanks Mark V. I wish it were that simple. My Crown Victoria is a 2004 and it does not have plug wires. Each cylinder has an individual coil. At almost $60.00 each for the coils at Advance Auto, I do not want to replace all 8 coils. Without a SE light or a trouble code, I cannot tell which coil is bad if there even is a coil problem at all.

About a year ago, I had a single coil go bad on my 2001 Expedition. It threw a trouble code that told me which coil was bad so I knew which coil to replace. Back in the day, I would have just changed the wires, cap, and rotor. The Crown Vic no longer has any of those parts! Thanks again for your help. Any other ideas?

[ABE]

Originally Posted by mark v

Time you change your Spark Plug Wires, they are bad. What is happening is the wires are getting wet when the snow and slush hits them and are shorting out. Pop your hood at night, start the car and look at the wires and you might see sparks jumping too, you can also spray water on the wires at night when it is running and see the sparks arc.

The '98 and up Crown Vic, Mercury Grand Marquis and Lincoln Town Car use Coil on Plug (COP) ignitions so there are no high tension leads.

[ABE]

Originally Posted by Dan07

Thanks Mark V. I wish it were that simple. My Crown Victoria is a 2004 and it does not have plug wires. Each cylinder has an individual coil. At almost $60.00 each for the coils at Advance Auto, I do not want to replace all 8 coils. Without a SE light or a trouble code, I cannot tell which coil is bad if there even is a coil problem at all.

About a year ago, I had a single coil go bad on my 2001 Expedition. It threw a trouble code that told me which coil was bad so I knew which coil to replace. Back in the day, I would have just changed the wires, cap, and rotor. The Crown Vic no longer has any of those parts! Thanks again for your help. Any other ideas?

Some people have complained about getting water down inside the plug holes and having shorted plugs. A solution proposed by the guru (DRock from Crownvic.net) is the typical lubricating of inside of boots with die-electric silicone grease and an extra bead of the grease on the outside of the boot to seal the opening in the head/intake manifold. This has apparently worked to keep out moisture.

Hope this helps.

[Dan07]

Thank you for your input Abe. It sounds to me like this may work. I will add some extra dielectric grease this weekend and wait for the snow. Adding more grease to the boots will also give me the opportunity to inspect them for cracks and tears.