Misfire issues

[SkiBonne]

Hey guys,
Have been chasing a misfire for a while now on cyl #3. At first it was rare, once in a while, now it's a constant issue at idle. It runs great cruising, but hates to sit at a light. Initially I changed out plugs and wires, swapped coils around, but still on #3. I even checked out the injector signal and threw in a new injector, with no change. Now I went ahead and did a compression check, #1 @ 135psi, #3 @ 90 psi, #5 @ 135psi. Did a wet recheck on #3, and came up with 100psi. I'm sure the rings are a bit worn, but that is still more than a 15% difference in the cylinders. My question to you is, do any of you have any solutions, short of replacing the head or having the head redone? Any advice is appreciated. Thanks!

[Archon]

If the compression came up by adding oil, you're likely looking at rings as the problem, not the head or gasket. Perhaps you chipped a piston?

[SkiBonne]

I don't think I set up the tester quite right, causing the disparity between the readings, and then made sure I had the same amount of cranks each time after. But I'm more than certain it's a valve issue, going to tear into it this weekend, will post results of whatever carnage I find.

[SkiBonne]

Performed a leak test and with both rockers loose air was gushing out the intake, inflating the glove I stuck over the throttle body. So I am looking at an R&R of the heads, should be fun. Any input for some performance upgrades while it is torn down? Or should I just pick up that nice 04 GXP with 90k on it...

[nos4blood70]

The GXP may or may not come with it's own slew of head issues… lol

You can port the heads, add rockers and stiffer springs, etc etc. How far are you trying to go with performance? You can always just grab another L67 head and throw it on there.

[harofreak00]

I have a 68k mile head for $50 + shipping if you want the easy route.

[SkiBonne]

Yeah, I've read the stories about the GXPs. Haro, That head does sound tempting, will let you know, thanks.