Intermitant firing of Cylindar

[johnm]

 
 I had a cylinder go dead on me while I was driving. (One closest to the firewall). I thought it may have been the fouled plug again but this time not the case. When I began to pull the spark plug wire and could hear the spark the cylinder came to life. But then when I installed the spark plug wire completely it went dead again. I tried it a few times with the same result.  I traded wires with one I know was working OK and the same thing happened on the same cylinder. I would appreciate some help as to what may be happening. Thanks very much

[Pawel66]

But have you replaced that spark plug finally?

[johnm]

 No about to order some new plugs but up to now have just been cleaning the fouling off it.

[Pawel66]

I have never heard about anything like this (but I did not hear a lot, really), but from your desciption it sounds like something is wrong with the connector on the plug or inside the plug. If you swap the plug, you will confirm if it is a plug.

I saw many times plug connector on the lead faulty, but you say you swapped the leads and the effect stayed.

[ja17]

Removing a plug wire while the engine is running, actually increases the intensity of the spark, just like increasing spark plug gap. In some cases a fouling plug can temporarily be cleaned and come back to life. Check to make sure the transmission diaphragm is not ruptured. If so #6 spark plug can get fouled from transmission fluid. Also check your #6 cylinder spark plug wire and ends for excessive resistance. For your information, you can hold the center coil wire away from its contact, and instantly intensify the spark to all six cylinders while the engine is running. Be careful not to shock yourself.

[johnm]

 I Think next I'll switch two of the spark plugs and see if the issue follows the plug currently in #6 cylinder. I'll report the findings. Thanks very much for the feedback on this issue.

[Shvegel]

I second Joe's comments regarding the automatic transmission diaphragm.  Happened to me,

[johnm]

 How do I check the automatic transmission diaphragm.
 Thanks
John

[ja17]

Disconnect the line at the manifold and see if trans fluid is in the line. Also if you have a mini-vac, you can check to see if it holds a slight vacuum.

[Benz Dr.]

I would think it should hold full vacuum. The engine pulls full vacuum while decelerating and even a small hole or crack will let a lot of fluid through. I once had a modulator diaphram blow out and I couldn't even see my house next door - that's how much smoke it made. In this case, the smoke is more white than blue which is engine oil in that case.

Do you see any smoke or is your trans fluid going down?