What causes a misfire?
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Joined: Feb 2005
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From: Ocean County, New Jersey

Carboned up spark plug(*), dirty air filter, improper plug gap, I think even a clogged cat can cause it but im not sure how. Bottomline can be caused by several things.
OBD2'* are designed to detect bad emissions or a misfire. If you experience a misfire the service engine light will flash on and off to alert you of a misfire. Not sure of OBD1'* however.
OBD2'* are designed to detect bad emissions or a misfire. If you experience a misfire the service engine light will flash on and off to alert you of a misfire. Not sure of OBD1'* however.
Also caused by crossing plug wires, [on distributer'd cars] the cap/rotor worn/timing WAY off.
Interferance from radio waves and the like.
OBDI does NOT detect misfires, at least mine doesn't. MAYBE OBD1.5
-justin
Interferance from radio waves and the like.
OBDI does NOT detect misfires, at least mine doesn't. MAYBE OBD1.5
-justin
Originally Posted by opensourceguy
Interferance from radio waves and the like.
OBDI does NOT detect misfires, at least mine doesn't. MAYBE OBD1.5
OBDI does NOT detect misfires, at least mine doesn't. MAYBE OBD1.5
OBD1.5 (94/95) PCM'* do detect misfires.
9 times out of 10, it'* a wire or plug. With the wires, it'* either an open, or a short arcing to ground. Both will foul the plug.
Occasionally, it'* a coil., rarely an ICM, as the ICM would take out all 6 generally.
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Hook up a scantool and watch the cylinder missfire data.... You will know if you have a dead on miss...
Yes the 94-95 Bonnies do display Misfire data
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Yes the 94-95 Bonnies do display Misfire data
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I think i mave a small misfire at idle. it goes away when i accelerate but i do have KR. I have new wires and the plugs are fairly new. I'll get some scan tool data within a week or so.
I'm still leaking a little oil from my headgaskets though so ultimatley that could be the problem. I'm still planning on replacing the MLS gaskets with regular felpro'* this summer but i have to save up some $ cause i'm doing more stuff while i'm in there.
Anyways
thanks guys, i'll keep ya posted.
I'm still leaking a little oil from my headgaskets though so ultimatley that could be the problem. I'm still planning on replacing the MLS gaskets with regular felpro'* this summer but i have to save up some $ cause i'm doing more stuff while i'm in there.
Anyways
thanks guys, i'll keep ya posted.
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