hi guys, I found this forum and was looking around and didn't find my answer. So here I am posting this up to see if I can get a answer from this. here is my problem

i just installed a new engine into my 98 jimy and it was showing a ckp engine code after starting but the car ran idle and drove perfectly fine, so I didn't care for it. I then drove it about 20 miles and the car started shaking very bad and having a very hard miss firing while i was on the freeway. so I got it back home and started to debug it. I first check the code and got a crank sensor p0339 and a p0341 cam sensor. the car still starts and somewhat trys to idle, it has miss firing like if the distro is off a few tooth and back first with spark knocking like crazy.

NOW: the reason im posting this is because ive done and changed almost everything I can and still have the damn problem. ive googled this and it seems like alot of gm owner has this problem too but with no really hard answer to what was the cause.

i've replaced,
cranks sensor
cut and hard wired the crank sensor
cam sensor
cut and hard wired the cam sensor
distro with a new cam sensor
check fuses
change ecu
check for all omh on all wiring to all sensors
change temp sensor
distro cap/rotor
changed maf
changed tps
check 12v to ecu and all grounds checked as well
changed coil and coil ignition module
moved distro 3degree retard, also moved it 3degree advance

and last i hooked up a datalog code reader and found that my rpm was skipping/jumping all over the place, from 0 to 4,000 rpm. fuel pressure at 60-63psi.

ive been on this car or over 2 months now and am sick of it, I just cannot think what can do this after all the above has been looked over and over and over again.

any help and suggestion would help me out alot. thanks for reading