04 LS V6 engine light/rough runner

[NicksGTR]

Has been extremely cold in NW Ohio, but finally took the LS to do some errands. After warm-up, engine light began to flash and run rough. I changed the plugs at 75k (now has 82k). I pulled the left side cop's on the chance I had a gasket leak but everything was dry. One of my IMT gaskets is leaking, so when I pull the upper intake I'll check the right bank. I'm going to check the pcv next, along with the hose and connections.
I used my x-cal under dash, but it pulled no DTC's.
Any other suggestions are appreciated.

 

[myfirstlincoln]

Could be a million different things form a vacuum leak to bad gas. When you replaced the plugs, did you also do the coils?

 

[joegr]

Flashing check engine light is always a misfire. The familiar advise applies. Replace all six COPs and all six spark plugs (yes, change the plugs again).

 

[NicksGTR]

Update: V6 rough runner

Flashing check engine light is always a misfire. The familiar advise applies. Replace all six COPs and all six spark plugs (yes, change the plugs again).

Disconnected the battery, checked the pcv (ok but oily), took the car to get gas and did a test drive (about 15min) and everything normal. I'm going to let it sit over night and do it again to make sure the pcm re-learned completely. No check engine-no misfire.

I ordered the O-rings for the IMT's and I'm thinking about adding an in-line oil separator in front of the pcv. The amount of oil in the upper intake on these cars is bull....