OK I am beating myself up trying to figure out what may be cause this! I have a 2000 LS1 WS6 with headers. I removed the EGR and plugged the whole in the intake. and a few months after in did that it started misfiring or running rough/bogging down. I can be driving along and it just starts, usually around start up and then goes away after ive been driving it a while. but its like it has no power and if i press the gas all the way down eventually it will take off! but then ill shift and it'll do it again. And it seems like it happens more often after it rains or especially while its raining! I thought maybe it had something to do with me leaving the secondary air hooked up so i unplugged it. I thought maybe that had fixed it but it did it kind of, not as bad, today on my way home from work and also it hasn't rained lately. I scanned for DTC's and just has secondary air (which i unplugged), o2 sensors (I don't have cats), knock sensor(that's been their since Ive had the car) and multiple engine misfire! If anyone has any ideas I would extremely appreciate it!

 

i know it sounds funny but i had the same prob it ended up being the clutch. it acted the same way for about a month and evenly on one really rainy day it just locked up and the clutch peddle stuck to the floor. after changing the clutsh i never had the prob again. maybe i'm just crazy but what ever the prob was fixed

 

wow lol i never thought of something like that. Oh, it also happened after i changed the plugs. but i thought maybe if it was a plug or two wouldn't it say cylinder 1,2,3,4,5,6,7,8 misfire depending on which one instead of just multiple engine misfire.

 

I used the autozone scanner and it told me exactly what cylinder was misfiring. It was a orange scanner. In the end it was correct as I blew a oil ring and it has oil all over the spark plug. You change the wires?

 

i had a problem like this, do you have the air induction kit that draws the air into the lid from down low?Mine was actually sucking up water. Ended up going through a deep puddle and destroyed my engine

 

Yes I replaced the wires as well.....Yeah I have the SLP lid with the metal thing that sucks air from below. But that has been on my car for at least 3-4 years....is it possible to finally start a problem now??

 

i would try taking just the metal plate out that draws the air from under the car and see if it still does it. I had that slp kit and it didnt do it for about a year. be careful because i had the exact same thing happening and one time when it was real wet i went through a deep puddle and i blew a rod all the way through the block and had to spend 5 grand on a new engine. I opened my air filter and it was soaking wet after i wet through that puddle.

 

I'd also recommend you check the weather stripping in the cowl area to make sure it's sealing right and not letting water drip down onto the engine, especially since you're coil packs and injectors are sitting right there, and the pcm is not far from being soaked sitting there in that one corner.

 

check the plug wires. they are more likely to arc under wet conditions