jmX

Short version:

#2 is misfiring when engine is cold, and really misfires under load when cold. Car almost wont accelerate up to 2500rpms when its real cold, and slowly that 'bug' fades out as the engine warms. Once warm, it isnt so bad, and is almost just fine. Car may be down 20-30 rwhp.

So, here's what I know:
1) Springs are fine. Valves appear fine, all stems come to the same height.
2) Intake port on #2 looks fine, no cracks from overporting that are visible.
3) Exhaust gasket around #2 is paper, and its black around that cylinder, as if doused in oil
4) Pulled #2 plug....coated in oil
5) EFI Live logged the car, #2 misfiring 100'ish times before the counter resets
6) Plug wire appears fine. Ohms out at 318, the other wires were 300's as well. (stock wires)
7) not the tune, i tried a stock one, a known old good one, and my current. No effect
8) EFI live logs look 100% ok other than the misfires.
9) Haven't noticed any excess oil usage, nor any smoke out the tail pipes. I do seem to need about 16oz of coolant every 3000-5000 miles, or at least I did once. Not sure if it was a fluke, could have been underfilled a bit since I did the meziere a bit ago.

Here's what I'm trying tomorrow:
1) swap coils from one side to the other, see if issue moves
2) swap fuel injectors, see if issue moves
3) compression test (i dont have a compressor to do a leakdown )
4) retorque the bottom 5 head bolts (ARP), checked the other 10 already and they were fine.
5) If all else has failed, pull the head.

Anybody got a guess as to what it is? It'll be fun to see who guesses it right, and maybe it'll help me think of some things to try. I'll get through this issue one way or another.

distortion_69

iTrader: (20)

I'm thinking if oil is in your cylinder and all the rest of the valvetrain appears okay that you are loosing compression at the piston/rings. Thats my guess, but I have no clue what I'm talking about.. I just wanted to guess.

Good Luck,

jmX

I'm defintly not ruling out rings or a piston issue, however, its an LS1...oil getting in the cylinder is a way of life thanks to the PCV. All intake ports had oil in them, #2 int. port didnt seem to have significantly more than the other 7 though. If the normal oil was getting in, but the cylinder never fires, then that could cause the oily plug since the oil would never burn off...or at least not until the car has warmed up and the cyl starts firing again.

However, it could be anything at this point, so your guess is as good as mine!

Colonel

I'm sure you've tried changing the plug on #2.

ABNRNGR (Aka Dean)

iTrader: (1)

o2 sensor

wrencher

iTrader: (2)

Really hard to say anything without knowing the compression is ok in that cylinder.
If it is fine either an ignition issue or an injector issue.

jmX

Colonel, I bought plugs yesterday and today I went and swapped #2 and #4. The problem seemed to move, so I then changed the #4 plug (which was #2) with a brand new one.

Car runs fine now....Going to put all fresh plugs in and see if the problem reappears on #2...something may be fouling the plug. Looks like this will be a "drive it and see" issue, because I'm betting #2 fouls again after some time.

niphilli

Plugwire would have been my initial guess.....

GrapeApe

cracked ring land --i hope not but it has happened-- or a bad valve guide

GrapeApe

or a sticking lifter -or bent pr ok im done

Brains

iTrader: (7)

nick a valve seal? easy enough to change 'em out on that cylinder, and cheap too.

cueball

thats what i was thinking, if not then it could be your #2 coilpack
i know that when there is more than normal resistance in the plugwire,plug
it will burn out the coilpack after awile of running that way
since you said that the plug wire ohms out good then a loose connection
or fouled plug
hope that helps