What happened to my DD?
 

About three years ago I bought a 2000 from Florida with 94K on it, flew down there from VA and drove it back. Used it as daily driver for a few months and it sometimes had a miss, eventually found out it was a bad fuel injector.....after replacing the $300 coil pack. That winter and found out the orange fluid in the radiator was not coolant but it was rusty water when it froze and cracked thermostat housing and water neck on back of head. I took the opportunity to make some stuff better.

I pulled head had it freshened up, replaced thermostat housing and water neck also installed reroute. I replaced header with a aftermarket one and lost the EGR and the CAT. Installed ARP studs (for future boost). Put it all back together and it ran great, got a CEL but I figured it was due to the lack of EGR. Put 7K miles on her this year and no issues except a vibration at idle that I just thought was due to needing a tune up, it has gotten worse. Finally got around to a tune up, replaced wires, plugs and started it up and the vibration was the same :vash:

I pulled codes and the expected EGR came up and also P0301? That plug did look a little different then the rest, not bad just a little darker. So I suspected coils again, swapped wires around and code stayed P0301. Not good. Did compression check this morning....cyc 1 #40 cyc 2 #170....I gave up there! WTF?

So ideas? What happened? What to check next?

Continue the compression test on #3 and #4. Either the rings are bad or something with the head on #1. Then leakdown test them to determine what exactly is bad inside your motor.

Pull #4 plug wire and run it, see if it codes P0304. The ecu may be out of sequence and coding for the wrong cylinder.
BTDT

What? Have you actually seen this? If so, what did you do to fix it?

The ECU determines which cylinder is missing based on crank/cam signals put together. I find it unlikely that it would mix this up unless one of the signals was shitty. By shitty I mean broken cam sensor.

Yes I have seen it B4 I think thats what BTDT means isnt it?

Still has 40 psi in #1.:idea:

Drop about 3-4 drops of oil in cylinder 1, if it goes up, your rings are bad

Or you can just start the leak down test right away.

+1

Here is the PIS info on all 4 cyc:

1 2 3 4
DRY 30 150 190 205
OIL in cyc 30 150 170 205
W/spark plug in 30 160 170 205

I have head studs on this car that have never been re torqued....could that be an issue? I also just just read thread on ARP head stud torquing and I'm sure I followed the ARP recommendations of 80 ft/lb not the 65 ft/lb that is agreed upon here. Issue?

Just got ahold of a leak down tester, post results soon.

I can't really see the head studs idea dropping your compression numbers to 40. Irrelevant really, unless you completely forgot to torque the front 4 or something.

Eh, if the head was warped or studs untorqued, you'd see SOMETHING in #2, if not #3 and #4 as well. It's something with the valves, rings, or rod on that cylinder.

Oh boy here are the leakdown #'s

1 100% (kinda makes a blow off valve noise when you open the throttle.)
2 30%
3 40%
4 25%