Hi guys,
First off, I wan't to thank everyone that helped me before with my head replacement/ Head rebuild a while back. The information was helpful. I Have the car running pretty good now... (besides what I'm about to go over)

So it idles amazing, perfect. There is no misfireing, no strange noise NOTHING.
Once I take it on the road however, it's gutless at the lower RPMs (which was not the case just a few days ago)
And in 2nd gear and up, when I really give it gas, it sputters and misfires.
I'm getting the following codes:
P0300 (random misfire)
P0301 (cyl 1)
P0302 (cyl 2)
P0303 (cyl 3)
P0304 (cyl 4)
P0455 (EVAP leak)
I've reset the codes several times, and it only gets them again once I GAS on the road. like I said, it idles perfect.
Things I've done:
Checked ALL vacuum lines and visually inspected PRV, and DV. Although I hear those are kind of hard to tell just by looking at them/testing them with crude methods. I've replaced the fuel filter. I don't smell fuel, and I don't notice any leaking from that area so I think I can rule that out.
I've visually inspected and cleaned the MAF and throttle body.
And last, and certainly the most dumb, I've replaced the gas cap with a brand new one. (4 dollar troubleshooting can't be beat)

I'm wracking my brain here, and I can't seem to find anyone with a similar issues (misfiring under load, with an EVAP leak)
I'm also going to throw this out there. All codes started at the same time, after about a 3 hour drive from western MI to Detroit. Shortly after getting off the freeway.

Call me nuts, but could a clutch going out cause a misfire or other problems? Not sure how many miles this clutch has on it (vehicle has 174k)

 

Are you dead certain the timing belt is on properly? On a 1.8T it can be a pain in the ads to set and tension it correctly - applying tension usually pulls it off by a tooth. If your timing is off, it can cause misfires under load. If you changed plugs during the head job, did you make sure that they're properly gapped at .032" if you're stock and .028" if you're chipped?

 

I'm certain on my life that the timing is 100% correct. I quintupaly checked it when I installed the new head, out of fear that something else would go wrong with it!

I'll check the gaps on the plugs as soon as I'm fully awake, i'm not chipped so It should be .032. I didn't mess with them between pulling them out of the box and installing them, hoping that's all it is.

I've heard that bad coilpacks can also cause misfireing under load.
I have 1 coil pack that's quite a bit older than the others, it's the only one that survived a tune

Also, would a bad sparkplug or a wrong gap size cause an EVAP code? That's really the code that's stumping me, I'm almost certain I can flag down the misfire, if that is infact all that is the case. Could it be bad PCV? Would you reccomend I do a catch can?

 

Checked plugs, gap is fine, and they are pretty new (under 1k miles on them)
Funny thing is... this morning after removing/cleaning all 4 coilpacks and plugs the only cylinder code I'm getting is P0302 P/D (as aposed to all 4 cylinders misfiring), I'm getting FULL POWER now in 1st and 2nd gear (every now and then 2nd gear will misfire) I'm still getting heavy misfiring in 3rd gear and up. I'm not getting an EVAP code anymore (P0455) which is strange... what could have possibly caused that before?
Something to note is, I noticed a bend/break in the insulation around the ground wire attached the ignition wire harness leading directly to the Coil packs (the one that bolts onto the valve cover, between coilpack 1 and 2) the wire is still intact, it just seems as though the insulation is damaged.
Also, I don't remember hearing it before (hoping it's somewhat normal) but I can hear a hissing noise coming from the area about where the crank case ventalation elbow is locked into the block. It's very faint, and only gets slightly louder when I give it throttle.
Sometimes I feel like a complete idiot when it comes to these things, I don't know what to check next, I don't want to start replacing things like coilpacks unless I'm certain it's what will solve it.
I am REALLY short on money now.

EDIT- Now I feel really dumb. I didn't even think to swap out coilpacks and see if it follows to the cylinder. I'm going to do that now!

 

strange.... now it's misfiring on Cylinder 1, and I swaped cylinder 2 and 3's coilpack...