Cat 426b Hydraulic Problem

I have been working on a hydraulic issue with a cat 426b. 11,000 hours. initial problem was after getting warm front loader would stop lifting. I installed a gauge on pressure port 3 which is signal pressure and found pump was strokiing/destroking rapidly. I changed resolvers, no change, changed entire loader lift valve with new, fixed the stroke destroke problem. i still didn't like the way it lifted so i decided to see if the cylinders were good. blocking off left then right i would watch the gauge i had 1800 psi and no cylinder movement with both. two bad cylinders? took one apart and the packing edge on the rod end was failed even wear but worn badly the rod nearly fell out of cylinder no tension at all. ok so i decide to check the system with no cylinders attached and plugs in those lines. after at operating temp, i can get a consistent 1800 psi from that function and bucket curl back function, clam closed gets me 3000 psi? what am i suppose to have and why do they function differently? Stand by pressure is 800 psi, its suppose to be 320-ish, if i lower my stand by to 320-ish i only get about 1100 psi. on the hoe end everything gives me the 3000 psi! HELP!!!!!!!TIO

Cat 426b Hydraulic Problem