Random misfire, misfire cylinder three

LMSUTHERS

MEMBER
2005 DODGE STRATUS
4 CYL
2WD
AUTOMATIC
51,507 MILES

I recently inherited the car from my mother who never drove it. In the last year she drove the car 400 miles. The check engine light came on as a random misfire, misfire cylinder two. Change spark plugs and wires. Check engine light was off for about 2 and 1/2 weeks came back on now it is throwing the code for random misfire and misfire cylinder two. Noticed I have had loss of power and it idles rough at a stop. The check engine light also flashes when I go slow or stop. It drives great at high speed. Changed the spark plugs when it threw a code for cylinder two several weeks ago. This past weekend I changed the spark plugs again when it threw the code for cylinder three. Inspected the wires and the boots and they look fine and the guy at the auto place said the coil pack seemed okay, and my check engine light is still on, it is still randomly flashing mostly when I sit still and it idles rough at a stop, no overheating although the fan does come on if you sit for a while with it running. Can anybody tell me what I should look at next? The only other thing I've noticed is my gas cap doesn't make that whooshing sound when I take it off. I replaced the gas cap. Still no whooshing sound. Help!

4 Replies

JACOBANDNICKOLAS

MECHANIC
108,200 POSTS

Hi,

The gas cap is likely not related. However, there are other things that can cause issues.

First, when you notice the check engine light flashing, which is an indication of a misfire. Otherwise, it would stay on solid. So, I need to know if the P0303 is the only code that is present.

Next, things such as engine vacuum leaks, fuel injection issues, fuel pressure issues, and so on can all contribute to a misfire. By chance, has fuel pressure been checked? If not, do that and confirm it isn't too high or low.

Here is a link that shows in general how it's done:

https://tipmrebuilders.com/product-category/2006/dodge-2006/caravan-dodge-2006/

If you look at pic 1 below, it shows the manufacturer's fuel pressure specifications.

Let me know what has been done so far and if you notice anything when you experience trouble. For example, is there any black smoke from the exhaust or odd odors?

Take care,

Joe

See pic below.

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Friday, December 17th, 2021 AT 10:15 PM

LMSUTHERS

MEMBER
3 POSTS

Hi Joe! When the check engine light first came on it was throwing code PO300 and PO302. Before that I had noticed that it rough idles whenever I am at a stop. My mother said it has always done that, so I didn't think a lot about the rough idle really until the engine light came on the first time! It rough idles, but it also flutters kind of. The RPMs are a little less than half of the way between the first line and the 1, and even when it flutters it really doesn't fluctuate on the RPM instrument panel. My mother only drove 400 miles last year and I have been driving it every day. The guy at the auto shop said I probably have a carbon buildup and to put Lucas or Seafoam in it when I put gas in. I put Lucas and twice, the gas and carburetor cleaner kind. It does not overheat and there is no smoke coming from anywhere or any kind of smell. I have not had the fuel filter checked or anything else the only thing I have done is after the first codes that it threw I changed the wires and spark plugs. The check engine light stayed off for about a week week and a half and then it came on again. When I checked it with the meter it was throwing the code PO300 and PO302. I had read in another Dodge forum to only run champion plugs, and I couldn't remember what I put in at the time before, so I changed the plugs again, using champion and the wires and boots were okay so I did not change them the second time. I tried to take the wires out of the coil pack the second time I changed the spark plugs but they seem to be in there really good and to be honest with you, I girled out and was scared to pull on them too hard! They seemed like they were seated pretty good and when the mechanic had looked at it at the auto parts store he said that the coil pack looked okay, so I just didn't really mess with it. Is there a trick for taking the wires off of the coil pack? Do they snap in? My last car was a Toyota Corolla and I wrenched on it all the time, but for some reason I'm scared to mess with this Dodge Stratus! Any advice you could give me I would greatly appreciate! Thanks again! -Lisa

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Friday, December 17th, 2021 AT 11:00 PM

LMSUTHERS

MEMBER
3 POSTS

Also, when I changed the spark plugs, there was no oil on them, they were not burnt up or fouled. They just looked like regular used spark plugs.

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Friday, December 17th, 2021 AT 11:05 PM

JACOBANDNICKOLAS

MECHANIC
108,200 POSTS

As far as the spark plug wires at the coil, they do click in, but to remove them I always give them a twist when pulling. Just make sure you are holding it at the boot and not the wire.

I honestly don't feel the wires are the issue. The idea that the idle is low and rough may be something as simple as an engine vacuum leak. That will cause a lean fuel mixture and oftentimes, it will cause a misfire and rough idle.

So, take a look through this link. It explains how to locate and repair a vacuum leak. Try this and hopefully, it helps.

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

Also, if your scan tool has a live data setting, I need you to check two things, short-term fuel trims and the signal from the engine coolant temperature sensor.

Let me know. Also, since the misfire has moved from cylinder two to cylinder three leads me to believe it isn't the coil either. The coil for the 4-cylinder engines fires two spark plugs every power stroke. One plug is the cylinder under compression, the other cylinder fires on the exhaust stroke. Cylinders 2 and 3 work on different coils, so it doesn't appear that one is going bad.

Let me know about the vacuum check and if you can provide the scanner info.

Take care,

Joe

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Friday, December 17th, 2021 AT 11:23 PM