2008 Dodge caravan 3.8 cylinder 1 misfire and random misfire.

Messages
225
Location
Illinois
Thread starter
My buddy has a 08 with the 3.8 and it's misfiring bad while driving. Went on test drive before and after changing plugs and wires. Coil looks good no burn marks, so I doubt it's that. It's worst under load and physically shakes at about 35mph. Next thing I'm checking is compression and after that it's getting a fuel filter and injection cleaning. Any help in diagnosis is greatly appreciated for this is his daily driver and he's a pizza guy.
 
Messages
225
Location
Illinois
Thread starter
It's got a single coil pack that controls all 6 plugs. It's to the right of the engine. It's coming up misfire on cylinder 1. Trouble codes 0300 and 301.
 
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12,782
Location
ROCHESTER, NY
Since you've already changed the plugs & wires, check battery voltage and for leaks/disconnected vacuum lines. Also for arcing in the coil pack area.
 
Messages
33
Location
MI
Lived this dream on our 2010 w/3.8L It was corrosion under the coil pack, where it mounts. Clean up the four areas and the metal on the coil pack. We purchased a Delphi unit on Amazon, worked great.
 
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225
Location
Illinois
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I have a really big junkyard about two miles from my location and will be pulling an oem Mopar unit with significantly less miles than his current unit. His is one with 157k miles. Thanks for the advice and will be doing it tomorrow. Wish me luck.
 
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225
Location
Illinois
Thread starter
And it sounds like it has an idle miss too, but it's definitely not as bad as when under load. It's was shaking pretty bad in the 25-40mph range on test drive after plug and wire change.
 
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22,054
Location
CA
Do you have a single cylinder misfire or multiple cylinders that are misfiring? That is something you need to figure out upfront. Otherwise, you are heading down the wrong diagnostic path.
 
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23,763
Location
MA, Mittelfranken.de
Originally Posted by Jetsfan421
It was the coil pack. He swapped it out and it's running smoothly. thanks for the help!!!
What diagnostic steps were done and what were the results that pinpointed the problem or was the parts cannon fired with crossed fingers? I enjoy the process of getting there, Cline does a great job with his diagnostic post.
 
Messages
225
Location
Illinois
Thread starter
They were original parts on the van. The plugs, plug wires and the coil pack. So I figured they could stand to get changed as a tune up of sorts. After the wires and plugs didn't do it practically everyone was saying coil pack so we decided it was the next thing on the list. I don't have any fancy scan tools, but have seen the videos on how to use them. Knowing a misfire can only be spark, fuel, compression and air I knew to start crossing the easy ones off the list. All in all I probably saved the guy a couple hundred in diagnostic fees and at least that in labor. Them back spark plugs were tough.
 
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