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Misfire PLEASE HELP!

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Old Mar 5, 2008 | 04:37 PM
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Default Misfire PLEASE HELP!

2000 SS

Over the winter I put AR Headers (Race) on. Since then I have drove it a few times.

I drove it for a while after work, was looking under my car while it was running and noticed the passanger cat was glowing a light red, and the drivers side was not. I got out the tech 2 to check misfire data.

Showed no current misfires. Went into Misfire History and saw

#1 & 2 had <10
on #3 had about 300
#4 had 2800!
#5, 6, 7, 8 < 10

I set the parking brake and loaded it up. No current misfires. Drove it home while watching the counter, got about 60 currents each on #7 and 8

Leave it running while opening the garage and the exhaust is popping like crazy, check the counter, and still no current misfires.

What gives?! The car has approx. 20K miles, original plugs and wires. Could this be an !EGR thing? (Still isn't tuned, and probably won't be till misfire is resolved). I am worried about killing the cats on my brand new y-pipe.

Oh yeah, I checked codes and had a P0300-Random misfire code. (+the egr and air)

Thanks for taking the time to read this and any suggestions are very much appreciated!
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Old Mar 5, 2008 | 05:34 PM
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Egr wont cause it to misfire,have you checked you spark plugs?One or two can be cracked,make sure your plug wires are all the way in.
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Old Mar 5, 2008 | 07:10 PM
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for sure pull the plugs and check them if not chenage them . also the plugs maybe suspect . a tune will wrok as well .
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Old Mar 5, 2008 | 07:55 PM
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i duno 20k on plugs sounds like somthing eles...one thing I noticed on this forum is it seems like every car has a misfireing problem all with different symptoms ..including me ...
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Old Mar 5, 2008 | 10:17 PM
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Wasn't there a recall or a TSB on the catalytic converters on 98-00 LS1 cars because they were failing? If your cat is glowing red it means its plugged. if you got the car from a dealership then they should've sent you a letter about the recall an they'll fix it for free. Hell even if you didn't im sure you could bring the car to a GM dealership an they'll still fix it for free--just tell them theres a TSB on the cats.
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Old Mar 6, 2008 | 11:38 AM
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Thanks for the suggestions..

Here's the update. I'm going to get the msd and ngk plug and wire combo, put those on and see if that doesn't help. I know a guy who does diagnostics, so I think I will have him current ramp each of my coils to make sure they're all good.

Lastly, I called livernois motorsports and asked them weather I should fix my misfire and then have it tuned, or if the tune may solve the misfire problem. He said bring it in, and the tune should take care of it. Any thoughts?

Thanks.

btw this is a bolt on only car
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Old Mar 6, 2008 | 01:57 PM
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Good luck with whatever you do
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Old Mar 6, 2008 | 08:55 PM
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never even thought of it the guy is right on the cat.
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Old Mar 7, 2008 | 10:11 AM
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They aren't stock cats, I believe american racing uses magnaflow, so a recall doesn't help me out here.

A plugged cat may glow red, but I'm sure a hot cat that has raw fuel dumped (from say a misfire) will also glow. Hope it didn't melt the substrate because then it will turn to a clog.
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