Pinto Car Club of America

I was told it was the flex plate that was loose, took the tranny out and the flex plate bolt holes were not round but elongated. My friend seems to think it is a motor problem. The motor has good oil pressure, and there are no leaks (oil).  I took a broom stick and place it at various point on the engine and put the other end up to my ear and the knock seems to be coming from the back of the engine and down low either on the block or where the bell housing connects to the block.
Any ideas, or other test I can run without removing and  tearing the engine completely down?

thanks in advance

I assume your car has an automatic transmission?  Were the torque converter bolts loose?  If so that is your problem.  I had the same problem about a year and a half ago on my crusing wagon.  I had a loud knock at idle and once the engine got up about 2000 rpm it would go away.  I more I got into it, the more I figured it must be the torque converter.  Once I pulled the starter and checked the bolts I knew I found the problem.  The bolts were loose for some time because they elongated the torque converter bolt holes in the flex plate.  I replaced it with another one for piece of mind.  There should be no elongated holes anywhere on the flex plate so it should be replaced in my opinion regardless.  Hope this helps....  Good luck to you