Piston Misfire

[John Wernet]

I have a 2000 Subaru Legacy Wagon and have had it for a year now. I notice
that every once and a while the #2 piston misfires, I bought a computer that
tells you what is wrong when the check engine light comes on, the car if I
try
to accelerate fast will buckle and hesitate very bad, so to correct this I
change the spark plug wire and it works fine. The spark plugs are brand
new,
Bosch, but I wonder if something else is the problem because only #2 piston
misfires?

HELP
John

 

[Jerseyj]

I have a 2000 Subaru Legacy Wagon and have had it for a year now. I notice
that every once and a while the #2 piston misfires, I bought a computer that
tells you what is wrong when the check engine light comes on, the car if I
try
to accelerate fast will buckle and hesitate very bad, so to correct this I
change the spark plug wire and it works fine. The spark plugs are brand
new,
Bosch, but I wonder if something else is the problem because only #2 piston
misfires?

HELP
John

Interestingly, my 99 Subaru Forrester hesitates and bucks ONLY when it's
extremely humid out, especially during heavy rain. This happens even
when it's parked out of the rain! Wonder if changing the spark plug
wires might help!

 

[-rick-]

"Jerseyj" wrote

Interestingly, my 99 Subaru Forrester hesitates and bucks ONLY when it's
extremely humid out, especially during heavy rain. This happens even
when it's parked out of the rain! Wonder if changing the spark plug
wires might help!

Take a good look under the hood in the dark. It can be quite revealing if
there's arcing going on.

-rick-

 

[David]

Take a good look under the hood in the dark. It can be quite revealing if
there's arcing going on.

Putting your fingers near the plug wires while it's running can be interesting too. Don't necessarily have to
get that close (depending on wire condition).

 

[Tony Hwang]

Putting your fingers near the plug wires while it's running can be interesting too. Don't necessarily have to
get that close (depending on wire condition).

Hmmmm,
I did not know piston fires. LOL!
Tony

 

[JWC]

John - I had a code indicate a piston misfire too (same piston
coincidentally). See my comments below that I copied from another response
about how it was diagnosed and corrected....

Re: 97 Outback: vibrations when idle in D
by "JWC" <(e-mail address removed)> Apr 19, 2004 at 09:02 AM

I drive a 98 Legacy Outback. My car was having similar problems. Idling
at
a traffic light in drive the car would vibrate or rock pretty
substantially. If I pressed the gas slightly, the vibration would lessen.

Though this was pretty annoying, I didn't think too much of it. When my
'Check Engine' light came on, I took the car to the shop thinking it was
an emissions sensor that would need to be fixed/replaced. They told me
the
Check Engine code indicated that I had a misfire in one of my cylinders.
At first they suspected a burnt valve, but further investigation found
that all I needed was a valve adjustment (with new shims or seats, I
think
that's what they were called). Apparently the valve wouldn't seat
properly
and this prevented the cylinder from achieving the necessary compression,
and with the periodic misfire, I was more or less driving on 3 cylinders
instead of 4. After having this fixed my car doesn't vibrate any more.
The bill came to a little under $700 (at the Subaru dealer) which also
included adjustments for the other valves while they had the engine apart.

 

[Guest]

Check Engine code indicated that I had a misfire in one of my cylinders.
At first they suspected a burnt valve, but further investigation found
that all I needed was a valve adjustment (with new shims or seats, I

What mileage was this at?

 

[JWC]

This was at about 102K miles

 

[Guest]

This was at about 102K miles

thanks

My manual calls for a valve adjustment at 100,000 miles, and I was
wondering if this is really necessary.