Howdy guys. I have a 2003 Town and Country Limited, with a 3.8 Liter. A couple of days ago I replaced the back valve cover gasket, because it was leaking oil. To do this, the upper intake manifold had to be taken off - no big deal. With everything torn off, I thought it was a great time to change out spark plugs, since I just turned 113k miles. Again, obviously no biggee. With the gasket and spark plug swap complete, I reassembled the motor. All wiring pigtails and vacuum lines are correctly fastened. Here is the problem. The engine has a miss when it is idling, and if you accelerate any more than 1/4 throttle, it will backfire to high heaven, and gain no speed or rpm's (generally happens around the 2k-3k RPM mark). Only when actively backfiring would the check engine light flash. So I thought, "Huh...", and I changed plug wires. The van seemed to be fixed, so i thought. But driving it home from the garage at my work(where I did the repair), it started backfiring again, but the CEL stayed on! So I thought "YES!", I'll have this sucker read and then I can properly diagnose this! It read Cylinder 6 misfire (P0306 I think). So I pulled the plug on 6 (front right cylinder, easiest one to get to luckily), and the plug looked brand new! Probably because it is brand new...lol. Then, with the engine running, I pulled the wire boot off of cylinder #6. It had a very weak spark - I pretty much had to touch the boot to the exhaust header to get a spark. I pulled the other two front cylinders, and observed hellacious sparks - it was a neat lightning show. So I put the O.E. wire back on the coil and with the engine running, I observed the same, insignifficant spark. So I thought it must be the coil pack! So I replaced the coil pack and ..... same iddy biddy spark... "Eff!"... This is my transportation for the kiddos, and my pregnant wife. It is tremendously important to get this rig back up and running. I can't be the first person to see or experience this, and I'm begging for a helping hand. Please, take the floor!

 

First things first....

On the coil-pak are #'s stamped in the casing...Are the wires on properly and to the corresponding cylinders.....????

Make sure you havent "PINCHED" the injector harness in the manifold seam.

swap plugs 4 and 6...if the misfire follows.....you have a defective plug.

 

The wires are in their correct spots. I reckon the injector is fine, since the plug smells like fuel and fuel consumption is through the roof. Swapping plugs makes no difference, and here is why... When I pull the wire boot off of the #6 plug, the spark is so, so very weak. The other cylinder's sparks are violent and right on the money. The OEM and the new coil pack are performing identically. Both throw great spark to all cylinders except #6. I didnt pull any wire boots off of the back because i was tired of getting shocked - lol! But I just don't comprehend why only cylinder #6's plug wire is throwing an insufficient spark through it. What in the world would make a coil pack decide to make 1 plug run at 1/5 or so normal spark?!?