Readers with good memories may recall that I had to replace wires and plugs in December during a road trip. More recently, I added 1.5 bottles of Red Line fuel injector cleaner before a road trip out of state. Two or three tanks of gas later, and this car is misfiring. It started out sporadically, but the engine light didn't come on until today, and is misfiring more frequently, especially in a stopped position. Coasting at 40 - 50 MPH is much better, but my wife complained it was bad on the freeway earlier today. (The 2006 GC has 106k miles on it, 3.8L engine.)

So, I took it to Autozone, and their OBD II reader coughed up a P0305 and a P0300. Considering the relatively new plugs and wires, the Autozone guy suggested the ignition coil. Since it was 10 minutes before closing and I had nothing else to go on, I bought it, figuring I'd come here to find out if that's the logical next step. If I put the new coil pack on, I can't take it back.

If the new coil pack is the answer, is it a simple swap? I.e., Do I need to be concerned with "syncing" the coil with the last cylinder firing? Is it a big deal to remove the power steering reservoir just enough to pull the coil pack out?

And, yes, we're out of town (again!) to attend a funeral tomorrow. My best opportunity to deal with this is first thing in the morning (crack of dawn), so if anyone is able to answer tonight, that would be most appreciated!

 

No, you don't need to do anything after replacing the coil pack. Except to clear the check engine light. How is the van running?

 

I would check your cylinder #5 plug and wire. Driver side, last or third cylinder back closest to the firewall. Take out the plug, make sure its gaped correctly and in tight (not too tight). Next inspect the wire make sure it didn't melt on anything and its fully secure on BOTH ends. Good luck and keep us posted.

 

Thanks for the quick reply!

master tech: The van is running poorly most of the time, especially when it idles at a stop. Accelerating up to 30 MPH misfires, but tonight it seemed to run a lot better after I got past 30 MPH. However, my wife drove about 80 miles today, most of it freeway at 75MPH, and reported misfiring most of the time, with a few intermittent stretches where it ran with no or very little misfiring.

dsolorio: Since I don't have my tools with me and I'd have to pull the wiper cowl to pull any plug on the back side, I won't be able to pull the plug. I gapped these plugs myself, so that should not be the problem. I will try to pull the wire tomorrow morning and inspect.

I was wondering if the Red Line fuel injector cleaner might be the culprit here. It "cured" the poor acceleration on the highway in the first tank. Is it possible the stuff it loosened fouled up the spark plug(s)?

 

The wire appears to be in good shape. It was on securely when I pulled it off the plug. There were no signs of any damage. I was also able to tell that the plug was not loose.

So, now the plan is to replace the coil pack. I removed the two top screws on the power steering reservoir, but something is still holding it on. Is it possible to remove the reservoir just enough to get the coil pack out without having to disconnect any hoses?

 

there is a 10mm nut under the reservoir pointing toward the cowl area, loosen it and lift the reservoir. Shouldn't have to remove any hoses.

 

it is also possible the fuel cleaner loosened up some crap and it is now stuck in the injector.

 

Not sure about the 10mm nut. Here's what it looks like on my vehicle (click to open up on ImageShack):




I've marked a "button" with arrows, not sure what this is or its function. Am I looking in the right place?

 

I was able to pull the spark plug (#5) and it looks fine.



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Ok Tizzy, I see the nut on the back side. Dang!

So I'm off to get a deep socket and a swivel extension.