Misfire Cyl 5

[Brandynr]

I keep getting a trouble code on my 2000 3.8, showing a misfire in cylinder 5. I cannot track down the cause of this misfire; hopefully someone here will be able to help. First, the steps I've taken...

I changed the plugs and wires. I changed the mass airflow sensor (needed to be replaced anyway). I had a friend test the fuel pressure at the rail, and check the voltage through the plug wires. I even added seafoam to the gas, thinking maybe the injector was dirty.

I had the same friend hook up his laptop to the ODBII port while I drove the van. This is what pointed me towards the mass airflow sensor being bad; it just wasn't the cause of this problem.

While I was driving it, he said he couldn't really see a major misfire (though I don't know what he might have been looking at); but it seems that the trouble light comes on mostly when it's humid (though it stays on until I have it reset most of the time).

Any suggestions anyone might have would be appreciated, and I apologize for the lengthy post.

[wiswind]

I know that I sound like a broken record....but I would put 2 cans of Berryman's B-12 Chemtool in the gasoline tank.
It is the only cleaner that I have found that will clean the gunk that builds up inside the end cap on the fuel injectors on my '96 3.8L.
It is one of the less expensive of the many cleaners at the auto part stores, but it seems to be the one that cleans my injectors the best.
I would try that first, as it is the cheapest and easiest.....as well as very likely to solve the problem.

After that, one would look at spark plugs, spark plug wires, and coil pack.

[MARZBX157]

Hi,

What spark plugs did you use? I know that some plugs don't work right in the windstar.

[Brandynr]

Originally Posted by MARZBX157

Hi,

What spark plugs did you use? I know that some plugs don't work right in the windstar.

Napa plugs, copper I believe... But I was getting the misfire before I changed the plugs; actually, it was because of the trouble code that I changed the plugs.

[bdahl385]

Originally Posted by Brandynr

Napa plugs, copper I believe... But I was getting the misfire before I changed the plugs; actually, it was because of the trouble code that I changed the plugs.

If NAPA really sold you basic copper spark plugs for the Windstar, I would run far away from that parts house and find a more knowledgeable place to buy your parts.

Do a search in this forum for spark plugs and you will see all kinds of problems when not using the OEM platinum plugs or a very short list of equivalents. Although you had this misfire before changing out the plug, you will probably soon have more cylinder misfires with these copper plugs. IMHO...