Diagram for Arctic

Bin working on the beast! an still have a Problm?
#First was Red hot real quick exhaust.
then as it got hot the ECM would drop the idle an things
would be good @ idle. rev it up to 3000 or 4000 an things
would get real hot real quick,like melt down hot.
so long story short ive checked everything 10x over.

Cat was clear when i checked it,took it off
an could see right through it,then used
the shopvac blower to check the pipes muffler
all clear.

Fuel--38 to 42lb steddy
injectors-bench tested 24 of them an pick the best 6
cold start is all so working

Ignition timing set with jumper in @8dg then 12dg
to many times to say its bin all over the place.
 an the harmonic balancer is true an not spun,checked.

An no Vac/leeks,eng will stall if choked all so did ether spray
an ox from a torch no leeks-tight

EGR is new an working,no leeks

--know after that and the last
putback togather,upper 2x intakes. it starts an runs
real nice an dosnt get hot @ idle an seams to be on
time an tune.New o2 sensor to.
SO heres the mud! @3000/4000+ only the rear
 3 CYL-2/4/6 get hot know/red hot-HUMMMMM?
this is odd,looks like ELE,bad ground not sure yet.
 still searching,i will find/fix it!
Thanks