91 Toyota Camry... Need help with spark plug diagnosis
 

I have a 91 Camry LE with 180k miles. Recently, it has been running
as if it lacks complete power. This morning I began to look at
variious aspects of the engine to determine the problem. When I
pulled the spark plugs, I notices that all of them had good appearance
(light gray in the firing area) except for one. My #2 plug has a
medium brown coating on the electrode and ceramic area surrounding the
firing tip. It is not oil fouling. I am running Bosch Platinum
plugs.

What would cause this?? Would this appearance of the plug idicate
that the plug does not fire at all... or, is it firing inefficiently.
I changed the plug wires about 8 months ago with Toyota OEM wires,
therefore, I can't imagine there is a problem there. Additionally, I
conducted a compression test and got 170 - 175# on all six
cylinders... including #2.

91 Toyota Camry... Need help with spark plug diagnosis
 

The color of the plugs is just one factor. How about the wear contours
on the electrodes? Go to the Bosch site and look at the pictures. You
could have just needed a set of plugs. You also have to wonder about
the timing, as in timing belt wear.

91 Toyota Camry... Need help with spark plug diagnosis
 

On Thu, 01 Dec 2005 20:46:59 GMT, (Al Kondo) wrote:

>I have a 91 Camry LE with 180k miles. Recently, it has been running
>as if it lacks complete power. This morning I began to look at
>variious aspects of the engine to determine the problem. When I
>pulled the spark plugs, I notices that all of them had good appearance
>(light gray in the firing area) except for one. My #2 plug has a
>medium brown coating on the electrode and ceramic area surrounding the
>firing tip. It is not oil fouling. I am running Bosch Platinum
>plugs.
>
>What would cause this?? Would this appearance of the plug idicate
>that the plug does not fire at all... or, is it firing inefficiently.
>I changed the plug wires about 8 months ago with Toyota OEM wires,
>therefore, I can't imagine there is a problem there. Additionally, I
>conducted a compression test and got 170 - 175# on all six
>cylinders... including #2.

I would suggest swapping the plug to a different cylinder and the plug wire with another and see
which shower the problem.
*****************
Thank You

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