another thing if you change to third gear when the knocking starts it goes away and the engine do not stall.

im just thinking about inspecting everything, taking out the spark plugs the valves check everything.

How about doing a back pressure check? could be a cat problem.....

the car has no catalyst, previous owner removed it :/

LOL has it passed the inspection like that ?

Big end rod bearing failure ?

ah here in venezuela there are not inspection, also the gas is so cheap that therrs no problem.

mmmm could you explain me that?