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Random misfire needing some help!

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Old 10-06-2010, 08:02 PM
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Default Random misfire needing some help!

Hey guys I've had my 2000 z28 for a little over a year now and haven't had any problems until yesterday. I had parked my car at a friends house over night and went out the next morning started my car and about half way down the road my shifter started to shake more than usual, then my ses light came on. I took it to a friends shop and used a scanner, it threw a p0300 code or random misfire, I checked pugs and wires then started it up and it ran fine but only for the rest of the day. Today I started my car all fine and dandy then the shaking began again. Would you guess be able to suggest some ideas where to start or what might be the problem, cuz I've heard it could be anything from o2 sensor to injectors to gummed plugs and so on. Any help is appreciated, thanks.
Old 10-07-2010, 04:26 PM
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Originally Posted by craZy28
Hey guys I've had my 2000 z28 for a little over a year now and haven't had any problems until yesterday. I had parked my car at a friends house over night and went out the next morning started my car and about half way down the road my shifter started to shake more than usual, then my ses light came on. I took it to a friends shop and used a scanner, it threw a p0300 code or random misfire, I checked pugs and wires then started it up and it ran fine but only for the rest of the day. Today I started my car all fine and dandy then the shaking began again. Would you guess be able to suggest some ideas where to start or what might be the problem, cuz I've heard it could be anything from o2 sensor to injectors to gummed plugs and so on. Any help is appreciated, thanks.
An o2 sensor could cause this to happpen. I had this happen when my 02 sensor wasnt working. Also how old are your plugs and plug wires? What brand are they? What gap our your plugs at?
Old 10-07-2010, 06:35 PM
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Originally Posted by craZy28
Hey guys I've had my 2000 z28 for a little over a year now and haven't had any problems until yesterday. I had parked my car at a friends house over night and went out the next morning started my car and about half way down the road my shifter started to shake more than usual, then my ses light came on. I took it to a friends shop and used a scanner, it threw a p0300 code or random misfire, I checked pugs and wires then started it up and it ran fine but only for the rest of the day. Today I started my car all fine and dandy then the shaking began again. Would you guess be able to suggest some ideas where to start or what might be the problem, cuz I've heard it could be anything from o2 sensor to injectors to gummed plugs and so on. Any help is appreciated, thanks.
Since you messed around checking the plugs and wires you seemed to have fixed it temporarily. You might have a broken spark plug or a plug wire that is not staying seated on the coil or plug. Did they all "snap" into place nice and tight?
But it didn't give you a code for a specific cylinder...right? That can be a ton of different things that cause "random misfires".

Get another scan to see how the 02 sensors are switching while the engine is hot and running............to rule those out.

A failing 02 sensor will totally kill your over-all power and the car will run rich and stumble when you accelerate.

I would not go WOT or get on it hard AT ALL until you fix this misfire........a bad misfire and hard driving can damage your engine badly....

.
Old 10-08-2010, 03:14 AM
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I am planning on doing a full tune up with my oil change. But one thing i noticed you said is the o2 sensor will make it run rich. I remember driving home and i would push the clutch in so i wasnt so ruff going up hills and i could smell that it was burning really rich.

And another question is, im getting ready to put long tubes in my car and a friend and i took all the exhaust off to make the install faster we left the cats and down pipes on. Would running it that way cause the o2 sensors to burn out or something?
Old 10-08-2010, 11:51 AM
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Originally Posted by craZy28
I am planning on doing a full tune up with my oil change. But one thing i noticed you said is the o2 sensor will make it run rich. I remember driving home and i would push the clutch in so i wasnt so ruff going up hills and i could smell that it was burning really rich.

And another question is, im getting ready to put long tubes in my car and a friend and i took all the exhaust off to make the install faster we left the cats and down pipes on. Would running it that way cause the o2 sensors to burn out or something?
I know there's a certain length that you need beyond the 02 sensors otherwise it can cause a problem. That may be the issue.

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Old 10-08-2010, 02:27 PM
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Originally Posted by craZy28
I am planning on doing a full tune up with my oil change. But one thing i noticed you said is the o2 sensor will make it run rich. I remember driving home and i would push the clutch in so i wasnt so ruff going up hills and i could smell that it was burning really rich.

And another question is, im getting ready to put long tubes in my car and a friend and i took all the exhaust off to make the install faster we left the cats and down pipes on. Would running it that way cause the o2 sensors to burn out or something?
So are all 4 O2 sensors still in the car??
Old 10-08-2010, 06:06 PM
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Yes I do have all 4 sensors still hooked up
Old 10-08-2010, 08:04 PM
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Update guys, I bought new wires and put them on and the car doesn't shake like it had been, but I hooked my diablosport tuner to it and still says I have the p0300 code along with a p0354 which I think it said coil problem. So maybe I need to change a coil pack or two.




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