Is there a 3.8 supercharged engine that will fit directly in the 2001 Monte Carlo SS? Or any other for that matter? I have an 01 and it’s having issues with once it’s warmed up it starts misfiring really bad. I’ve changed the plugs, wires, coils, and the crankshaft position sensor. Nothing seems to fix the problem. Also, when you shut it off after it’s warmed up it will not start again for 30 minutes - 1 hour.

 

So to answer the question, yes you can swap a L67 (Supercharged 3800 Series 2) into your 2001. Engine can come from a Grand Prix, Regal, Bonneville, 04-05 Monte, Impala. I don't know all the process but from what I recall, fairly easy, pretty common. The PCM or PCM programming is the only potential difficult issue.

But are you looking to swap the engine OR sold the misfire? If you are looking to sold the misfire, let's start with, does it have any check engine codes? Also, you said it starts misfiring badly after it is warmed up. Any signs of white smoke from the exhaust?

 

I’ve been really wanting to swap the engine but if I can just fix the one in the vehicle easier I will just go with that. I’m not seeing any white smoke at all or any fluids mixing…I also had replaced the mass airflow sensor.

 

Yes, the L67 (supercharged 3800) is virtually the same engine you currently have. They're so similar in fact, that you can even 'top swap' the supercharger from one onto your current engine.

There isnt a whole lot to it as its almost completely plug and play:
-bolt in complete engine
-only difference bolting in is the connection to the transmission. The SC torque converter is a different diameter in the bolt pattern to the flexplate, so either grab the TC with the engine or an aftermarket converter with correct diameter
-plug harness back in
-address the wiring differences - map is in a different location and bbv solenoid can be wired in / hooked up (optional). They sell a $20 'L67 swap wire adaptor' that fixes this.
-address the fuel line connection locations
-flash the pcm with the SC engine tune (several 3800 suppliers offer this service via mail)
-enjoy

Its about as simple of an engine swap as you get in any car.

Since you seem open to fixing your current engine, I'd at least try taking it to a good mechanic to at least diagnose the problem. Id strongly suspect it'll be cheaper / easier to fix your current engine that drop in a whole new one (which may also have its own issues since you're buying a used engine).