Engine misfire
#11
02-01-2010, 11:50 PM
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P0300 is a multiple cylinder misfire, meaning more than one experienced a misfire.
It's not going to be a single plug failure. A multiple cylinder failure can be anything from a simple vacuum leak in the intake manifold or throttle body to a defective EGR all the way up to a blown head gasket.
It's not going to be a single plug failure. A multiple cylinder failure can be anything from a simple vacuum leak in the intake manifold or throttle body to a defective EGR all the way up to a blown head gasket.
#15
02-02-2010, 02:40 PM
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I would swap the cylinder 1 coil to a different cylinder and see if the code follows it to that cylinder to verify its bad. Then maybe get one from weedahoe (unless he wants to be rid of them as a full set).
#16
02-02-2010, 03:33 PM
#17
02-02-2010, 05:27 PM
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Today we checked spark plugs, and all of them had some sot build-up on them, none of them were wet from fuel not being burned, or any bit cleaned off.
#18
10-23-2012, 04:56 PM
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#19
10-23-2012, 05:17 PM
#20
10-23-2012, 11:58 PM
If you have JUST the P0300, the misfire monitor MAY catch a single cylinder misfire if you run it a little after the new plugs were put in...and if you didn't clear the memory....that will disable the misfire monitor and you won't be able to enable it again until it's running right, so it won't set a code again) If it doesn't catch and isolate a single one, then you are going to have to do it the hard way. Do a compression test....i'm thinking a broken valve spring. If ONE of the cylinders becomes seriously disabled for whatever reason, it will effect the rest of them almost as bad if not equally as bad. That ONE cylinder brings the vacuum down so low, the rest of them go nuts too. The P0300 is the only way the PCM knows how to interpret what's going on.