Help with misfire code

rjaywhit · Post by **rjaywhit** » 14 Nov 2011, 13:37

Replace cap, rotor, and leads.

rjaywhit · Post by **rjaywhit** » 15 Nov 2011, 06:59

How do you test the coil? I noticed that it is ticking, is that normal.

Any recommendations for spark plugs for this vehicle?

Thanks.

Post by **jblackburn** » 15 Nov 2011, 07:15

Bosch super copper plugs. Autozone sells them. Gap to .03".

Look under the hood with the car running at night. If you see any blue arcing around the coil, which I suspect might be the noise you're hearing, the ignition coil is bad.

rjaywhit · Post by **rjaywhit** » 15 Nov 2011, 07:30

I don't see any arcing. I hate to spend the money on a new coil if it's not the problem.

Post by **jblackburn** » 15 Nov 2011, 07:36

A (truly) bad coil would be causing misfiring on more than one cylinder.

I would start with the swapping the injectors and put some new plugs in there to start diagnosing things.

rjaywhit · Post by **rjaywhit** » 16 Nov 2011, 08:28

Yeah, When I pulled the spark plugs - 1, 3, and 5 were all normal and 2 and 4 were carboned up. So the coil must be ok if 1,3, and 5 are getting good spark. 2 and 4 are at the bottom of the dist cap and I saw a lot of carbon dust around those contacts.

I just thought of something that might be causing the rough idle and running -

Two Saturdays ago I removed the screen from the flame trap. It was cold that morning and I had to pull the MAF cable hard to remove it from the air cleaner housing.

The next day, Sunday, was when the rough running started.

Should I put the screen back in?

How can I check the MAF cable for any shorts?

Post by **jblackburn** » 16 Nov 2011, 08:35

Leave the screen out. It has no purpose except to clog up.

Do you have codes for the MAF sensor? A2 and A6? It won't cause misfires on just 2 cylinders, though.
http://www.volvospeed.com/CheckEngine.php

You said you replaced the cap and rotor, right? If the plugs are carboned up, change them as well. Too much gas and no ignition can foul a spark plug.

rjaywhit · Post by **rjaywhit** » 16 Nov 2011, 09:01

So far I've replaced the plugs, leads, cap, and rotor. Still getting cyl 4 misfire codes.

The plugs are Motorcraft Copper - Autozone did not have Champion or Bosch copper.

I have only read codes on A2, I'll see what comes up on A6

Post by **jblackburn** » 16 Nov 2011, 09:05

Chances are if that plug was all carboned up, so is that cylinder. One of the valves may be sticking slightly and not allowing full compression in that cylinder.

2 things I would try (after a compression test to confirm my theory):
1) Drive the snot out of it at high RPM for 10-15 minutes to try to unstick the valve.
2) Seafoam treatment into the intake manifold. It really helps dissolve crap in the cylinders.

kiss4afrog · Post by **kiss4afrog** » 16 Nov 2011, 12:45

Second the Seafoam treatment.

Help with misfire code

Re: Help with misfire code