The cap and rotor is usually part of a new Nissan distributor. They didn't need to replace the knock sensor because it was interpreting the chugging as a knock moment. What were the codes for the repair order? They are required to list them in order to perform the work. The flashingCheck Engine Light means that the code is occuring and being stored at that moment. The chugging could be associated with many other components like the ignition coil or things other than the ignition. It could be the fuel system related (fuel pressure or injectors), EGR valve, Mass Air Flow Meter, or even valve timing.
1992 S13 240SX SE Fastback KA24DE 5 spd
1993 U13 Altima SE KA24DET 5 spd
1990 Z32 300ZX VG30DETT 5 spd
Still trying to import a 1988 R31 Skyline GTS-R w/ RB20DET-R