1985 Toyota Supra missing knock sensor

I have a 85 Toyota Supra. I purchased a while ago with a bad engine. I replaced the engine from a junk yard. The engine came from a if I recall correct a 83, perhaps a 82. The junk yard told me the engine would work for my 85. They closed down in a short time after I purchased the entire car.

I put that engine in my 85 and I have had problems with the car running like crap. I put in new plugs and wires. I had the timing checked. I was told the timing was originally off by a jumped timing belt and it was then set to specs. They said it had good vacuum and that the check engine light was specifically on for the knock sensor.

Depending on the mood of the car, or perhaps the day of the week, it will sometimes start and idle so so, some days like crap. I have to rev it up to get it started down the road. It has a hard time getting up and moving. Some times when I go down the road, if I do not put the pedal to the floor it will help. The max I can get is perhaps 60mph.

I did try to rig up a spot for it. I took out a motor mount bolt, took a piece of steel, drilled out a hole all the way through and one half ways through. I tapped out the half way hole. Then bolting the piece of metal to the block where the motor mount bolt was. Screwed in the knock sensor and plugged it in. It did not help any. This spot is a bit far from where it is supposed to be.

What are you diagnosis? Do you think it would be the knock sensor giving problems or something else? I have pondered taking off the intake and either drilling and tapping a spot where it is supposed to be, or taking JB weld and sticking a piece of metal to the block and then putting the knock sensor in that. How exact to the factory spot does it need to be? A inch or 2 off factory spot ok?