Can someone please help me with what this is?

The sensor or whatever on the top rear of the block right behind intake with the plug coming out of the white part.

Trying to find a replacement for it but not sure what it is.

Thanks.

 

Well, your description is confusing to me, at least...

The FRONT of the engine is to the right in the pic, so the rear of the block is to the LEFT. So the only sensor I see on the top REAR of the block is Yellow, and probably is the oil pressure switch.

Around towards the front of the engine, I see a white sensor on top of an intake runner, that could be an IAT (Intake Air Temperature) sensor.

And further forward, another sensor that is White or Gray, if it is into a water crossover, then I would expect it to be an ECT (Engine Coolant Temperature) sensor.

And further forward, and a bit lower down, not far from the water outlet area, is a single-wire sensor, probably the coolant temperature sensor for the temp gauge.

But that's all the sensors I see, unless there is a hidden sensor that I am unable to see in the pic, like a Where's Waldo sensor

 

yeah i figured it out finally. good to go