2004 GTP purchased a few months ago, ran pretty well.
I'm a mechanic, but this problem is kind of weird..
Initially i noticed an occasional stutter or hesitation / misfire on low speed, small throttle openings.. and the cranking times were getting long. It used to start with a quick tap of the start position but then required up to a full second cranking to get it to actually start instead of cough and immediately die.
I had pulled two EGR codes from the computer before, and obviously a sticky EGR could lead to the problems, so i was planning on changing it anyway.. then yesterday it got strange.

On the highway, almost at my destination, it dropped one cylinder (at least) and started flashing the check engine light constantly. The light stopped flashing after maybe 10 seconds so i went the last 2 minutes to my destination. Drove it home again afterward and while the CEL never came on it did misfire at higher throttle positions and RPMs so i babied it home. Pulled codes and found the EGR codes again and a misfire cyl #3. Since cyl#3 is right next to the EGR port i figured that might be related, so i bought a cheap EGR and installed it last night. When i installed it, I did clean the flange surface but the valve did not seem to sit well on the flange, as though either the flange or the valve was not flat and this was making the valve rock slightly. But i went ahead and installed it anyway.

First test drive, It starts like it used to (quickly) but i hear a hiss when on the throttle and can feel a stuttering misfire (especially at boost) making me think the egr is not sealing up well (or the coil is going bad).
I take the egr off (the hardware was not as tight as i expected) and inspect it and the flange, everything looks fine so i put it back on, a little tighter this time.
Slightly less hiss, but otherwise No change.

The gasket i used was a thick papery style with the screen on the exhaust side, but it is terribly conforming so maybe its not offering enough crush to seal.
I'm thinking about using a graphite style.
I'm also considering picking up a coil for 3/6 just in case that is the issue now.

Anyone have any input on this?