Yes it can be unplugged from underneath, the plug sits on top of the transmission. I'm currently having the exact same issue with my front O2 sensor. It's sitting at my house now waiting for the new stainless steel cat pipe to come in.

If by "fit" you mean swap the engines, then not without an enormous amount of time, money, and custom work.

The upstream o2 sensor

 

I have currently have a hemi and a transmission on the side. was just wondering if itll line up and fit into the 2001 style. o2 sensor unplugged did the exact same. but this time its at the shop! Just gonna have them take a look at it and go from there. Thanks!

 

Probably another sensor getting hot then.

Let us know what ya find out.

 

its taking the dang shop 3 days so far. they cant figure anything out on it other than its sucking air. hopefully the boss come in and gets it running tonight! will update when returned

 

Finally figured this dang problem out.. it was a burnt hole into the piston. $$$$$ hopefully end of this week its up and running like a beast!

 

Ouch, time to upgrade to a V-8?

 

If money was rolling in faster... This girls broke! maybe next time.

 

Yeah, know how that goes.....

 

well crappp. its not the piston. now its the head. hoping this part is hell of alot cheaper than a piston plus labor!! hoping its back in good hands today and they aint saying it is something else!!!!!!!!!!!!!!!!!!! its been a month without my truck. <-- feels like this is what they tell me every update i get.

 

Odd you weren't getting misfire codes if it's indeed either one of those issues??