I didn't receive any header gaskets with the headers, only the HO2S gaskets, so I reused the OEM metal gaskets. The gasket on the driver side was defintely leaking as evidenced by the soot marking. The passenger side seems to be sealing with the old OEM gasket, I didn't see any soot build up around the top side of the gasket but I couldn't see the bottom side. It can be replaced with a new one if needed.

 

You might have a faulty coil pack. I'd get the code scanned to see if it tells you which cylender is misfiring, then swap coil packs with another cylender and check the results.

Shane

 

You might be right, it could be a faulty coil pack. Would I have to have it scanned at a dealer, if not, where? I'm going to replace the plug wires and plugs on the passenger side before I go that route, but then again?

 

Hang in there!

 

If there is a local tuner in your area see if they can pull the code for you and find out which cylender. If not then you'll have no choice but to go to the dealer.

Shane

 

This thread has really got me wondering what is up.. Keep us posted on the problem and how you resolved it

 

Aren't you supposed to use new round port LS1 gaskets GM Part # 12558573 rather than the OEM oval port gasket. Sound like you still have a leak on the driver side.

 

Nope! Not according to the Gents at LG's shop. I should have read the instructions a little more carefully, I was supposed to purchase an OEM gasket set for a 2000 Camaro, apparently they match up perfectly. Anyway I have the round LS1 gasket on now and it's not leaking, yet. As for today, I did replace the plugs and plug wires with brand new ones. Plugs gapped at.060 and new wires with the OEM metal heat shields. Started her up and she ran great for a couple minutes then again the misfire appeared. So I let her cool down and pulled the code, P0300 and the CEL was flashing. I cleared the code and started her up again after about a 30 minute cool down. Started and idled smoothly for a couple miniutes the the misfire started again. Did the same thing 2 more time with the same result, easy start up and smooth idle, even revving it right away was smooth but after a couple minutes the misfire reoccured. Since this is the third set of plugs and plug wires I am going to eliminate those. Since it starts and runs smoothly for a few minutes I thinkmI can eliminate the coil packs. Now, that leads me to the only other thing I messed with during the install and that is the O2 sensors. Again, they are connected correctly, right side to rifgt harness and left side to left harness. I swapped them from side to side but no apparent change. The person I talked to at LG's today(I can't remember his name) confirmed that a faulty O2 sensor could be the culprit, especially since it starts and runs fine till warm up. He did say to use only an OEM replcemnt from Chevrolet. I guess I'll try that next but probably can't get one till Monday or Tuesday.

 

now,i'm assuming it is misfiring @ idle,not under a load as before,correct.if you think it is o2's[possible,though without seeing the car it's tuff to diagnose],go unplug them and run the car.if the misfires are gone with them disconnected,they may be bad.just make sure you are not lean[air leaks/vacuum leaks/etc.],because with them disconnected you will be running on the rich side[bias voltage=.450mv].
usually they will pop a light for lean/rich/transition time,etc.,along with misfires.pull out the o2's and see if they are funky looking[black/water spotted,etc.]

 

Actually, it's doing the same as before. It's just that I left for a test drive while it was still cold. Today I just let it idle and warm up without going for a drive and putting it under a load, other than revving the engine. When I swapped the sensors from the left to the right side I did notice they were extremely black. I compared them to the front ones from the manifold and the fronts were fairly clean, kind of a rusty brown color. I'll stop by the shop on the way home from work and try your suggestion. Thanks!

 

Listen here meticulously. I had the identical problem a week ago and none of these things seemed to check out. Turned out that dpd was ABSOLUTELY CORRECT. He gave me the advice to get to the bottom of prob. I just had to take everything apart to understand that.

I repeat: One of the things above is your problem.

 

Finally resolved, I'm pretty sure. I disconnected both O2 sensors from their respective wiring harness, started the engine and let it idle to warm up. After a few minutes I checked for any codes but there weren't any (a good thing). Went for a 20 mile drive and no misfiring at all. Rechecked the codes and had a P0134/p0154 which I expected with the O2 sensors unplugged. I am going to order 2 OEM rear O2 sensors and just replace them both. I want to thank everyone for their input in helping me resolve this issue, especially "dpd" for hanging in there with me, thanks Don.