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2G Misfire on #2 - P0302, Nothing left to change! Help a 1996 Eclipse GSX

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Scottinalaska

Probationary Member
29
2
Jun 28, 2017
Anchorage, Alaska
1996 Eclipse, automatic, completely stock
Code: P0302 - Miss on #2 cylinder.

All four NGK plugs and wires are new.
Fuel pressure: in spec at 45psi at all RPMs
#2 Spark plug is black, appearing rich condition while other plugs are more white in color showing good burn.

Replaced Coil that operates #2 and #3
Cleared codes and drove. Miss on #2 remained.

Swapped fuel injectors #1 and #2.
Cleared codes and drove. Miss on #2 remained.

Swapped ALL new plugs putting #2 plug into #4.
Cleared codes and drove. Drove fantastic for 2 miles, then miss started again. Miss on #2 remained.

Swapped plug wires (new) between #2 and #3.
Cleared codes and drove. Miss on #2 remained

Compression check: #1: 180, #2: 160, #3: 190, #4: 145

90 octane gas. Fresh oil change.
Is there something I have missed? Compression isn't even. Is oil causing a misfire? Ideas? Thanks!
 
Well, as it turns out, there was one more test I did not do: A leak down test.
Recall my compression numbers here:
#1: 180, #2: 160, #3: 190 #4: 155
Now for leak down values at 75psi:
#1: 11, #2: 11, #3: 74 #4: 44
WOW!
#1 leaks into # 2 spark plug hole
#2 leaks into #4 spark plug hole
#3 leaks no where
#4 leaks into #3 spark plug hole and maybe a bit into the intake.
I am thinking the head comes off no matter what. Is the gasket just failing? Cracks?
No overheating issues. No bubbles in the coolant.
Thanks!
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Scott, I hesitate to ask because I don't want to insult you, but did you rotate the engine by hand to make sure all the valves were closed on the cylinder you were testing? Usually when I do one of these, I pull the valve cover off and pull all the rockers out so that I know the valves can't possibly be held open anywhere.
 
Yes, by hand. TDC every time.
You can see the screwdriver in the mating hole in a couple photos up out of the cylinder resting on the piston top (1&4, 2&3).
With #1, I used the crank marks as well.
Thx for being bold to ask. I'm bewildered how she ran OK at all!
Scott
 
I'm baffled by the compression test results being higher than standard in 2 cylinders, the mechanical timing being correct and the leak down being so terrible. If you hadn't just done the timing belt, I'd swear it was off at least a tooth.

At this point I think you're going to have to pull the head. I won't even venture a wild guess at what you'll find.
 
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