Ok here I go again.
This time it is my sons 3.2 cl.
He has misfire codes on all cylinders.
I checked all vacume hoses.
We "seafoamed' the engine 3 weeks ago.
Changed the plugs.
Put in NGK Iridium plugs.
Cleared the codes.
Now they are back.

Any ideas?
ECU?
Coils?
What would be the moest cost effective way to trouble shoot this?

Thanks as always for ideas.

 

I get the same crap. The codes come and go. Let him go through a full drive cycle and the codes will probably clear themselves.

 

Hows the car running? Is it noticeably missing?

 

No it runs OK no noticible miss

 

I had the same problem w/ my 3.2 CLS after I changed my spark plugs. The problem lasted for about a month, where the CEL would come on w/ several misfire codes. I could tell that everything was firing as it should and cleared the codes. The CEL would be off for about a week and then go off again 3 days later on its own.

Like I said, this happened for about a month straight (December 07). As of now it has been off since xmas and no problems.

As a side note, sometimes I noticed that when I would fill up w/ quality gas it would go off on its own when compared to some crap gas. Try that, no guarantees, but it worked for me oddly enough.

 

It had the misfire code prio9r to the plug change.I cleared them and changed the plugs now they are back.
Like I said we "used seafoam prior to the plug change, also an can of injector cleaner. I am thinking next is to disconnect the battery, to reset the ecu and see what happens.

 

From my past experience the type of fuel used goes a long way. Try using a full tank of Chevron or Shell brand gas. In addition, pick up a can of BG44K for about $30.00, pour it in the tank during the fill up. It sounds as though your fuel system needs to be cleaned.

I personally follow this process 3 times a year, and have not experienced a misfire.