defueling or low fuel pressure dont know what to call it

[03 6.0 smoking-n-knocking]

ok im going to tie this to my other theard bad lag on take off
did the egr cooler delete last week finished truck mid week drove it.
it didnt fill right like half to quarther power it had. ok took it to my buddy
he doesnt work at a dealer but scan tool for his feet trucks it give a code
p2285 injecter control pressure low circuit or voltage.also checked fuel pressure pulse swicth or wacth reading 16 rev it up an it drops to 9
the load is 23to 24. almost sound like its defuel we checked something for
map sensor reading 14 revved up didnt move changed out with a used laying around the shop reading 16 an moving. as for icp reading 639 idiling an the
ipr reading was 25%

also if 90 degrees outside an drive it for awhile an cut it off for shopping for
a hour an jump back in to leave its fine til u get a stop sign or light an have to wait a for a few mins. it act like its gonig to cut off an the egt guage starts douncing around if u let it set it will cut off an it will crank right up no wait time.

any suggestions,help, anything would greatly appreciated thanks
an lost at this point of no return please help me.