1991 240sx engine truble

[smokey91]

complete ly rebuilt motor new timing set, ran perfect for 2000 miles then slightly started missing like lossing spark going down the road i pulled over then it started missing bad and valves were making knocking sound yes it was coming from about 3rd cylinder in the head, it is still in time, it sat for a day dosent miss any more but it sounds like valve is hitting or clattering loudly, do you think it could have broke valve rtaner or somthing

[s13sr20chris]

you need to pull valve cover and have a look. could be a broken spring or something. could also be problems with shim/bucket assembly or even camshaft. in fact it could be in the reciprocating assembly(bottom end) but we hope not.