Did you install a long block or a short block?
Did you use the sensors from the old motor?

Neal

 

You need to pull up the misfire log and see if this issue is related to a few cylinders or to a bank. If you find it is a bank issue check the reading you are getting from the O2 sensors, Swap the O2 sensors between the left and right bank and see if you can get the problem to move to the other bank. Also, make sure your grounds in the vehicle are good especially the ones under the vehicle.

My guess is the problem your originally had followed the hardware you installed into the new engine. Also, did you re-use the injectors from the old engine? How about the fuel pump have you check the rail pressure? I would also still suspect the knock sensors (if these are the originals from the other engine I would put that close to the top of the list right after the ground checks) If they were corroded or rusted in anyway just replace them now.

Here is a great video on actually testing the knock sensors:

 

Have replaced the cam senor but not crank. Going to order gm crank sensors today and have installed next week fingers crossed it works!

 

It's the long block. All sensors are new except the crank sensors so going to order some gm ones and try

 

We did transfer a couple things over and crank sensors for sure are the old ones so we have some gm ones ordered and will install asap. My bf says fuel pressure is good and we replaced the o2 sensors. He is going to replace the crank sensors as soon as they get here. Fingers crossed it works! I miss my baby T.T lol

 

If the new motor came with anti-knock sensors make sure you run the test on them, the codes you mentioned can be thrown by these sensors, if they are the originals don't screw with them, just install new ones and make sure to clean the connectors when installing them.

Im also assuming to took the 24 tooth reductor wheel from the old motor and put it on the new engine, I don't think it would even start if you used the newer 58 tooth one. Stay strong, youve got a new motor there's not that many things that can cause the codes your getting.

 

A crank relearn will more than likely need to be done once the sensor is replaced

Neal