…ya…A whole lot of stuff i already tried.
Wouldn’t he hear it if it was piston slap?
to get a misfire code the pcm detects no acceleration at the angle of the crank where that cylinder should fire… Honestly I think you would need next to no combustion or cylinder pressure to set that code. If even a halfway decent combustion took place 90% off the time it probably wont throw a code. All engines missfire a little and the PCM allows for that.
soooo wtf is it? lol
Im thinking I damaged that plug doing my header install…
true but gm,s are very touchy on the missfires due to there very tight emmisions there under by law so any detection is noticed unless its a bad c.p.s wich i doubt
rims are ok, i like the stock ones though too. time to lower her!
Hey john, my buddy John that helped my tune my car…just looked at my file we scanned. He said me PE fuel enrichment tables have been changed before…He said someone leaned the car out from idle to 2K…this is his exact words…
“your car has been tuned before though”
“your idle is different than stock”
"your VE is leaned out @ 15-20kPa up to 2k RPM
“other than that, it’s stock lookin”
maybe the car with the headers is too lean now at idle and under load in 6th @ 1400-1800rpms?? and thats setting a misfire?
fuel tables would vary EVERY cylinder… you would have a multiple cyl misfire… not just #5 if it was too lean would be my assumption unless they disected the fuel trims by cylinder rather than as a whole… get new plugs in it and get a proper tune on the fucker… even if you ARE getting more shit in the future… tune it for what it has now… it may be the difference in a puked motor or one that keeps chugging for another 50k miles.
Fuel tables vary per cyclinder?
No such thing on my car I dont believe…
Its one single fuel map.
well, 2 technically if you want to do fuel tuning with the MAF…but thats a whole other ball game vs the PE table.
on the tuning software used to tune my car i BELIEVE you can isolate cylinders and adjust fueling… im not 100% positive on that but with a full standalone it CAN be done with the hydra or an aem.
if the problem persists after you put in the tr55’s i would pop the valve cover off, maybe all you need to do is adjust the rockers/valves a little.
There is no valve/rocker adjustment on an LS1. You bolt the rockers down and the bolts are torque to yeild so I dont recomend messing with them unless you want to order a set of rocker bolts. A few companies do make reuseable ones… I have them on my L67
yah I was gonna say the same thing…they arent adjustable. When you first install them, they adjust themselves I believe…after that, you dont touch them…
pulled the #5 plug today…doesnt even look like the damn thing is firing compared to the #7 cylinder one I pulled out next to it, which was completely brown and burning nice…these plugs have been in for a few hundred miles, and the #5 plug has a tiny brown spot on the porcelains…the rest is all white like its brand new…
Go back from the plug via the wire to the ECU and diagnose. Seems like you are on the right track. Did you check the wires?
yes, they look to be pretty good and no visible damage to the naked eye…
I checked the wiring harness early this morning on coil #5 to see if their was any frayed wires or anything of that sort…looks good as well…
I re gapped my old plugs down to .50 (was .60)…their denso plugs. I cleaned the tips up and porcelain with a wire wheel. Im putting them in now to see if the misfire still occurs so I can completely rule out the bad plug theory.
If its not firing it should could be wire on back to ECU. The eye can’t solve all. 
pin out the harness with a fluke or an equivilant voltmeter and check there is power at the terminal
ok just changed all the plugs…
cylinder #7 was REAL brown…all the other plugs were the same and looked still like brand new…
why is #7 different then the other 7?? Maybe theirs a problem with 7 but the PCM is picking up the activity for some r eason on #5?? These cylinders are right next to each other.
switch coilpack 5 with 7?
i thought you took it to the dealer to get it fixed?