injector nock has come back

[94TDsuburban]

Ok I have some nock coming from the #6 cylinder, I've cracked the line and it goes away, I've put a different injector in, same thing, I've moved injectors and it stayed at #6 cylinder. I have'nt checked compression yet but my scan tool gives me a code 96 #6 cylinder fuel failer. Could this be a pump problem or did I score a cylinder... Thanks
Oh another code I got was a 74 TIS ciurcit does anyone what this code is???

[94TDsuburban]

Can the injection pump be doing this???? anyone

[JohnC]

Can the injection pump be doing this???? anyone

Unlikely. If changing the injector had no effect, i'm going to guess you have a piston problem, or maybe a bearing.

74 is a transmission code (Input shaft speed sensor).

[94TDsuburban]

OK check compression tonight has 450lbs on the #6 cylinder and when I started it this morning it sounded like one from the drivers side was nocking to, have'nt check the injector yet thow. So I thought that maybe a rocker had moved on the shaft but thats not it either.:confused: :confused: