Quick answer. This 2006 Grand Caravan had misfire codes on cylinder 3 and cylinder 6, plus a general misfire code. Our tech tested it and found the spark plugs were fouling out. The job was one hour of diagnosis, three spark plugs and one hour of labor. The total was $299.
Key Points
- The scan showed P0300, P0303 and P0306. Those say the engine is missing, not why.
- Our tech found the spark plugs fouling out. That was the cause on this van.
- Three spark plugs at $8 each, one hour of labor at $125, and $150 of diagnosis.
- The scan also listed transmission and ABS codes. The record does not show work on those.
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What Came In
A 2006 Dodge Grand Caravan with the 3.3 liter V6. The work order said one word. Diagnostic.
That is a fair way to book a job. The owner knew it ran wrong. They did not know why. Neither did we, yet.
What the Scan Tool Said
Our tech plugged in a scan tool first. The screen filled up fast.
The top three were the ones that mattered for how it ran. P0306 is a misfire on cylinder 6. P0303 is a misfire on cylinder 3. P0300 means more than one cylinder is missing.
Below those sat more codes. A battery disconnect code. A gear ratio code in second. A 2 to 4 pressure switch code. A wheel speed sensor code on the left front. Some of those can show up after a battery has been off. We are not going to tell you what they meant on this van, because the record does not say.
What the Tech Found
A misfire code tells you a cylinder is not firing right. It does not tell you if it is the plug, the wire, the coil, the injector or the engine itself.
So the tech tested. The answer was the spark plugs. They were fouling out. A fouled plug is coated with junk, so the spark does not jump the way it should. The cylinder misses.
What It Cost
2006 Dodge Grand Caravan, October 8
Came in with: runs wrong, booked as a diagnostic.
Scan showed: P0300, P0303, P0306 misfire codes.
Tech found: spark plugs fouling out.
Done: three spark plugs replaced.
Cost: $150 diagnosis, $24 plugs, $125 labor. $299 total.
The diagnosis was $150. Three plugs were $8 each. One hour of labor was $125. That came to $299.
Compare that to guessing. Three misfire codes look a lot like bad coils or a bad engine to someone in a hurry. Testing first kept this a $299 job.
Every step of this job went on the record in Shop Desk, the software we built in our own San Jacinto shop. Other mechanics can use it free.
Frequently Asked Questions
What does a P0300 code mean?
It means the engine computer saw misfires on more than one cylinder. It is a symptom code. It does not name the broken part.
Can bad spark plugs cause a misfire code?
Yes. On this van, fouled plugs were the cause of the misfires. A coil, a wire or an injector can cause the same code, so it needs a test.
How much did this misfire repair cost?
$299. That was $150 for one hour of diagnosis, $24 for three spark plugs and $125 for one hour of labor.
Why were there transmission codes too?
The scan stored them, and a battery disconnect code was on the list. The job record does not say any transmission work was done, so we will not guess.
Should I just buy coils when I see a misfire code?
No. Test first. On this job the coils were never on the bill.
Supercanic tip: A misfire code is a reason to test, not a reason to shop. Call us at (951) 904-2477 and we will find the cause first.
Engine Missing or Shaking?
One hour of diagnosis, $150. You see what we found before you pay for a part.
