New TCV, now misfire codes??

[xlr8ing]

Hi everyone,
I tried to search this, but had no luck.
Quick history on the issue I'm having.
Bought my S60 2.4T last August. Ran good, but never seemed like it had the power it should for a turbo car.

2 weeks ago installed a Autometer boost gauge, and only making 4 psi, so I order a new TCV last Thursday. Not stock Volvo, but aftermarket stock replacement.
While waiting for that to come in, the car stumbled twice on the way to work last Friday. Take it out at lunch and it starts missing like crazy, and check engine light comes on. Cyl 4 misfire code. Tried changing the plug first, but no luck. Changed the coil, and problem solved. I also changed the rest of the plugs, but they were done last September, shortly after I got the car.
Right after I changed the coil, it starts making more part throttle boost, still not holding more than 4-5 psi to redline, but ran way better all weekend.

Monday the new TCV came in, quickly installed it, and BAM more power than I ever expected, and holding 8 psi to redline, and part throttle response is WAY improved.

Today, Tuesday, check engine light comes on again, flashing, which I know means a misfire, but the weird part is I was cruising while it happened, and no stumble or any drama from the engine at all. Car still makes the same power, and runs great.

My ride from work to home is about 40 minutes, I have a GoPoint GL1 hooked to my iPhone and was clearing codes as they came on. Codes were random, but included P0300 random misfire, P0301, P0302, P0303, & P0304, which coincide with cyl 1-4 misfires. I'd get random pairs too. Sometimes cyl 3 & 4, sometimes 1 & 3, sometimes 2 & 4, etc.

Could the new TCV cause this? I even tried watching the ign advance when it came on, and was at 39º when I noticed. I don't know if this is normal or not honestly. But during cruising it seems to be between 30 and 39º.

Is there a break in procedure I missed for the new TCV? There wasn't anything in the box it came in.

Thanks!

[xlr8ing]

Just to update, Wednesday morning the car started running like a bag of crap, and I had to change coil #2.

Ran good again after that, but was still getting random misfires.

So Thursday night I decided to reinstall the stock TCV, and the stock Volvo spark plugs that I pulled out. Unfortunately there was no change, and still getting random misfires.

Today I got thinking about what else it could possibly be, and I realized, it's gotta be a vacuum line issue. The old lines going to the TCV are quite hardened, so as a test, I cut about 1/2" off each line and reinstalled them. On the drive home tonight, no engine light!

So tomorrows task is to change all the TCV hoses, and see if that solves it once and for all.