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misfire 3.8L dodge engine
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hollerg
New User
Apr 13, 2011, 11:20 AM
Post #1 of 2
(3147 views)
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misfire 3.8L dodge engine
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I have a 2005, Dodge grand caravan 3.8L with 75K mi which has again developed a misfire. Their are no electronic codes or indication with scope. The misfire is erratic but frequent when at 50 mph and slightly accelerating. At idle and under strong acceleration there is no miss. No carbon
This happened once before. The dealer finally pulled the head and found one valve with pitting. Regrinding and reassembling solved the problem for about 20K, just long enough that the extended warranty has run out. This feels like swapping parts without addressing the mechanism that lead to that valve pitting.
So assuming I have a similar issue with a valve or two, what is the root cause that should also be corrected? I do not want to go through this again. (e.g. What should I ask the mechanic to do to avoid it re occurring?) Any idea whether the problem a malformed cam not properly timing a valve, weak springs, valve material of construction has too low a temperature range or strength, etc?)
If there is an upgrade for the problem, what brand or how to specify would be greatly appreciated.
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Tom Greenleaf
Ultimate Carjunky
/ Moderator
Apr 13, 2011, 11:46 AM
Post #2 of 2
(3133 views)
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Re: misfire 3.8L dodge engine
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Hmmm? A few things on the maybe list. I doubt cam, valve spring but a maybe is just a bad valve or seat. Not sure why you aren't getting a code with a misfire? I've seen a valve throw s pie slice chunk at 160,000 miles with a totally cared for and unamused car known from new. Car wasn't near me but have seen the valve. Fix was all new valves, valve seats and more figuring bad metal just happened and why it waited so long I'll never know. Surprised it doesn't misfire at idle.
Also surprised the fix the first time lasted 20,000 miles. Guess I'll suggest a machine shop put in all new valves, seats and guides if this car is a keeper and diagnose it again that it's the same issue,
T
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