(SOLVED) Dead cylinder at idle? Low temp on header collector

AJ/FormS said
bad exhaust valve.
Check for suction at the tailpipes, with engine idling, obviously.
Or do a Leakdown test,

Funny how your first mention is super similar to the effect he was having with the open EGR ports on the floor. Nice guess AJ! Well done.

macdrew77 said
SOLVED

I threaded a pipe plug into the floor of the intake and now she idles like a kitten. So much smoother, vacuum is up to 19.5 inHg and temperatures are much closer.

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I was reading the thread but I could not figure this out in my head. I didn’t notice the OEM intake. Also to be honest, I would not have guessed the floor jets making this kind of ruckus. I e always sealed them up from the get go figuring…. WHY-O-WHY would I want them open in the first place?!?!?!

Glad you got to the issue and ….. (LOL) plugged up the problem!