I've seen P0300 many times on stock 4.8,5.3,&6.0s in the vehicles they originally came in and a handful of times it blew my mind but was actually caused by a failing/failed 02 sensor. Infact on a particular Tahoe it shut down all 4 cylinders on bank 1. Watch your 02sensors on live data if you can and see that they are switching correctly. I have no experience with an ls series motor in a third gen so thisay not apply. Btw I'm subscribed, I got a 5.3 on the stand for my GTA.

 

I'll be able to check more when I get the laptop out in the car. Light ended up turning off later that day.
Car seemed to run great whether the light was on or not, so maybe it was some fluke thing.

 

Very possible, I put a new transmission control module in a Chrysler the other week, flashed it and test drove it about 20 miles. Customer picked it up and drove it for a while and called me and said it went back into limp mode. I went to his house with my scanner and car had no codes whatsoever. Drove it and it was fine. I have no doubts that he was right as I know him and he is a typical gear head. Sometimes these things just have a brain fart.

 

Yep, maybe it was just cranky that day. lol
I am really excited to do some tuning, Epecially to play with
the transmission parameters, Firm the shifts, and change some shift points.
Also currently I will get a random upshift to 2nd even with the shifter in manual 1st gear, which is really annoying, can't wait to tune that out.

 

Happy 4th of July!

 

missfire code could be a few things.

If I remember correctly:

1.) Cam swap, increased overlap fools the 02 into thinking its richer/eaner than it really is.
2.) O2 sensor on that bank will be reading overly rich (unburnt fuel) so could be failing 02, burnt harness, etc
3.) Sticking injector?
4.) cam/crank relearn
5.) Intermittent wire issue?

 

New development on the case of the missfire, not long after I got the code the first time, I noticed my torque converter lockup was being kinda finicky, it'll fall out of lockup at random times even high speeds cruising with light throttle. After doing some research, I stumbled upon this thread explaining that if the computer sees missfires, it'll unlock the torque converter at times. You guys think the LS6 cam was enough of a change for the computer to detect more missfires?
Here is thread I stumbled on with similar issues
https://www.bangshift.com/forum/foru...-out-of-lockup I need to get my custom tune done badly... Only thing slowing me down is the 3 hour trip to my friend who is good with HPT.

 

The LS6 cam is a decent bump over the factory 5.3 cam.
Stock 5.3 cam is:
-1999....191/190 .457/.466 115.5
Part # 12560966

-1999-2003....191/190 .457/.466 114
Part # 1256097 (Some 1999's had this cam)

LS6 Cam

-2001-2002 LS6....204/211 .525/.525 116
Part # 12560950

-2002-2003 LS6....204/218 .555/.551 117.5
Part # 12565308

The smaller 5.3 will make the LS6 cam act larger so it should have alittle lope to it. That being said my 218/228 .561/.561 114.5+5.5 def has alittle lope to it in my 5.3.

Cam overlap causes more fresh air to be in the exhaust and thus gives the 02 a leaner 02 reading (aka missfire). Personally I dont feel that the LS6 is enough to cause that.

 

Just double-checked, I have the bigger cam #12565308, thinking I may need to change the threshold in the tune for misfires.
Also it dawned on me that my current plug wires are the ones that came with my 5.3 when I bought it, so who knows how many miles they have on them.
I did a quick cylinder balance check by unplugging each injector one at a time. Seems like its running on all 8.
Really need to get some tuning done.

 

i doubt the plug wires are an issue. But u should verify spark at each cylinder.

I cant believe your not running a tune. The stock 5.3 timing tables are horrible compared to the LS6 tables. Not to mention the knock sensors are very sensitive and there are tons of tq modifiers and spark retard is very aggressive.

 

I am running a truck tune, but with LS1 spark mapping, that's about the only thing that has been changed.

 

Finally managed to make the 2 hour drive to get some tuning done!


Was able to add 4-5 degrees of ignition timing with no knock (26-27* total)
firmed up shifts to my liking.
Disabled torque management
My issue with converter lockup ended up being some tables in the tune that were conflicting each other.
Moved the rev limiter up to 6700rpm, shift points set to 6400rpm.
Pulls great up to 6400, its a real screamer on the highway kicking down into 2nd gear!


Overall very happy, of course there are always things to improve and upgrade, but as of now, the car is super fun to drive everywhere. Even averaged 22mpg on the trip, which included a lot of WOT pulls while tuning and lots of highway cruising.

 

Pretty solid results at the track! Once I get the 60' down, I think it could be a mid 12 second car! I am throwing some Nitto NT555 tires on the back to replace my bald Falkens, hopefully that'll be enough to get me into the 12's!

 

That's more like it! Personal best so far is 12.78 @ 109mph
Even touched 110mph on another run, not bad for a little mild 5.3!

 

 

did you use a guide to drill that hole?