Am I able to replace my 4.3 V-6 with a used engine from another yr. and not getcodes?
 

Does anybody know if I can replace my 4.3 V-6 in my 2000 Blazer with a used engine from a 2001-2002 model without problems? I'm worried, as my mechanic says there will be driveability issues. Did GM change the cam or sensors or will the ECU need to be updated?

may or may not be issues. Id grab the computer from the other truck and just plug that in when you do the new motor. Would eliminate that possibilty. Id keep the other computer and try that first and see what happens if nothing then your good if so you have the other computer to swap.

Mid year in 2002 GM changed the 4.3's by removing the EGR valve. Your 2000 4.3 has an EGR. I think you'll be ok if you get an engine with the same engine code. On my 2002 it has a "W" engine code & I replaced it with a 2004 engine of the same code. Just as an example.

thanks guys! do have the other truck's ecu but really just want to bolt my existing intake onto the used engine and then plug-n-play without having to re-invent the wheel. thanks again.

I believe Rottidog has the right idea; if they have the same engine code, you are probably OK; otherwise, there may be trouble w/o getting the ECM too. My 2001 Blazer actually has an engine from a 1998 C/K series, but all the connections matched up because they're apparently exactly the same engine model. That's not always the case though, because GM made small changes here and there over the years (like getting rid of the EGR) that will confuse some ECMs if you plug them into the wrong engine. Making sure the new engine has the same code as your old one is a good start. (Or you can grab the new engine's ECM to be safe.)