Hello All,
I recently got an 89 blazer with a bad idle well the egr plate i made fixed that and its been running great.

I started towing my drift car to the track and its been great but about 4 days Its started running weird while i was towing. I got it home (less then 2 miles away) and noticed one of the injectors had come unpluged. That fixed the problem but after driving that night i noticed a small knock....now it is a very loud knock and i cant figure out what it is.

It is a 4.3 and oil pressure is fine a little bouncing when I would hit bumps but around 40 and stedy with the knock, no lights exect a brake light flashing but I think thats sepperate

List of stuff ive changed/checked

Timing chain checked and tested
Changed oil (no shavings what so ever)
Turns over clean

My next step is compression test. But im wondering if im missing something important?

Compression test showed everything good execpt i couldnt get to one but here is the video of the sound

www.youtube.com/watch?v=S3mySgEhDKo

If I need to rebuild I have access to another engine a 98 cpi i belive my other question is should i rebuild that with an eddlebrock manifold and put it in my truck?

Any advice would be great thanks

Any help would be great.
I just picked this truck up and i really enjoy it
Im sorry for any spelling mistakes im on a tablet and cant see that well thank you again.

 

you have a rod knock,or a cracked flexplate. Remove the torque convertor cover,and get you a flash light. look at the plate and see if its cracked. if it looks ok,your stuck with a engine replacement.