Spark Plug Questions

[muzzymaniac]

Been trying to beat the idle vibration. I decided to change out the plugs. The original plugs are different on the passenger side than the drivers. I vaguely remember reading a reason for this but I can't remember why or where I read it. The passenger side plugs looked great as I expected. The drivers side all show a bit of wear and the rear drivers side has a bit of ash on it. What are the causes of the ash and is it bad enough to worry about?

Passenger side on the left - driver's on the right.

 

[bisjoe]

Light gray or tan, depending on the gas, is normal. I'd be more concerned that the one on the left, at least in the picture, seems to have some oil (black) on it.

Just eyeballing the pic those gaps look too big to me.

 

[cybergasm]

I had the same thing when I pulled the plugs on my '91 with heavy wear on the electrode like the one on the right in the pic.

i looked it up online and i found that it means the plug(s) has been in the engine too long.

BTW i just pulled my new ones today after have been in there for couple of weeks and the issue has not come back.

 

[muzzymaniac]

Yeah the pic is a little deceiving with the left plug. No signs of oil at all. The gaps were all at .060 or higher. New plugs went in and I guess I'll just have to watch that rear plug. Only one plug with ash on it is a little unsettling.

 

[cybergasm]

When I pulled the old set both plugs that has the eroded electrodes/ash were in both middle cylinders.