Sounds to me like a piston rod could be or beginning to break. Has the engine ever been over revved or anything? I had the same problem on my 1991 honda civic, thats what it turned out to be.
What Does A Loud Knocking Noise Come From The Motor?
Means, no fun!
By the way, when you say "Loud Knocking Noise"---does it sound like someone banging a hammer--really fast (about 5,000 times a minute)-against a wall.--means you got problems with your pistons and/or Rods.
More you drive it, more HOSED you're going to be! (by design, that chamber where the piston resides is supposed to be "air tight" (so the "explosion" can occur--*Grin*)...If that thing even has as much as a BB's worth of "excess space" in that chamber...you're causing bad problems---and a new engine is in your future.
---OR----
Is it more "tin" sounding (like metal hitting metal)----the latter could be a valve/lifter problem.
Either way, hate to be the giver of bad news, but you better start saving up NOW!--pulling out/replacing an engine is not cheap!
By the way, when you say "Loud Knocking Noise"---does it sound like someone banging a hammer--really fast (about 5,000 times a minute)-against a wall.--means you got problems with your pistons and/or Rods.
More you drive it, more HOSED you're going to be! (by design, that chamber where the piston resides is supposed to be "air tight" (so the "explosion" can occur--*Grin*)...If that thing even has as much as a BB's worth of "excess space" in that chamber...you're causing bad problems---and a new engine is in your future.
---OR----
Is it more "tin" sounding (like metal hitting metal)----the latter could be a valve/lifter problem.
Either way, hate to be the giver of bad news, but you better start saving up NOW!--pulling out/replacing an engine is not cheap!
Could be you flat spotted a roller rocker,rocker, dropped a lifter.
Means time for a new motor
It could be a rod bearing going out