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Misfire HELP

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Old 12-10-2007, 07:36 PM
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Default Misfire HELP

i just installed pacesetter lts and tsp ory. i had a real bad tapping noise and i found out it was the #8 plug was loose. lol woops.

so i put a new plug and wire on it and i still have a misfire on that cylinder. i also have a misfire on cylinder 1 and 7 it seems like the misfire is just jumping around.

my car stumbles real bad when i get on it in third gear and forth. seems to be fine in first gear.

what could this possibly be i have new plugs and wires to put in the rest of the cylinders and i am gonna do that tomorow do you think this might fix my problem????
Old 12-10-2007, 08:44 PM
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I had the same problem you have right now.... Make sure you are running the highest octane you can right now. Use shell or cheveron gas. It sounds like you have bad gas. The same thing happened to my vehicle when i got bad gas. Also if you ran your tank down low if there was any build up in the tank it all went to the injectors and might have ruined them. So you should also try Lucas injector cleaner. Bad gas will make your car run lean. Also if you just put the headers on the car isnt tuned for them the low backpressure will make your car run even leaner. Running too lean will make you misfire especially if you got particles in cirtain injecors and not in others. It would cause just those injectors to misfire. I hope this helps. Let me know... I suggest shell premium.... Also change your fuel filter when you put more gas in and change it 2 more times the next 2 times you fill up. Good Luck! Oh and make sure your plug wires are snapping on good and making good contact. I had an instance where the plug wire connector wasnt snapping on right and making good contact, clean them if you have too....
Old 12-10-2007, 08:55 PM
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Also try adding some fuel stabilizer... ethanol screws **** up so dont let it sit and then try running your car without fuel stabilizer.
Old 12-10-2007, 09:27 PM
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i will try that tomorow i only have a quarter tank of gas
Old 12-11-2007, 09:13 AM
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ttt! anyone
Old 12-11-2007, 11:39 AM
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ok so i drove my car with the scantool we have at work when driving i was getting a bad miss on #3 and a slight miss on #1.

at idle i was getting random misses on just about every cylinder.... but my idle is fine.

popped the hood and found that #3 spark plug wire was loose, then i drove it and it runs pretty darn good.

but myscan tool is still giving me missfires at idle? i dont understand this
Old 12-11-2007, 11:41 AM
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Bad knock sensor?
Old 12-11-2007, 11:51 AM
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Check to make sure your o2 sensor wires havnt been melted by the headers.... also do you have a full exhaust or are you running headers only, headers and y only.... ?
Old 12-11-2007, 11:54 AM
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Also remember that with bad gas your car will act funny for the next few fill ups..... especially when you you just put headers on and the car isnt used to them. Just change the fuel filter the next couple of times you fill up and use the lucas injector cleaner.
Old 12-11-2007, 12:00 PM
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i am running lts with an ory threw slp lm1 with cme so its full exhaust. i jsut filled the tank up and i replace the fuel filter not to long ago my car only has 17000 miles on it. i will try some injector cleaner though and maybe some fuel stablizer.
Old 12-11-2007, 01:49 PM
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Good, let us know how it goes...
Old 12-11-2007, 10:52 PM
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so today after work i installed all new acdelco plugs and wires, making sure i made all the right connections tightned all the plugs. started it up and it runs fun no misfires at all while driving. i also added some fuel stabilizer and a injector cleaner. the scan tool we have at work was still showing that i had random misfires at idle..... my idle is perfect the car seems to run fine? no codes nothing i am lost maybe the scan tool is crazy
Old 12-12-2007, 02:40 PM
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The scan tools will show some misfires at times,usually its ok just as long as the misfires are not able to be felt or trip the engine light.
Old 12-12-2007, 06:35 PM
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I bet you had a cracked spark plug and didn't notice it. Check all the plugs to see if you can find a black mark on one of them where the spark could jump through.
Old 12-12-2007, 06:43 PM
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mabe your gap was off in your plugs? did you check the gap before installing.....sometimes they get banged around in shipping and the gap gets off a little...
hope your running good now though
Old 12-12-2007, 06:57 PM
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check your coilpacks. how many miles are on the car, these are notorious for going out around 70,000 miles or so...




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