2 weeks ago I got a P0300 fault, multiple misfire, and the R was chugging along when accelerating. I had recently installed an LS7 clutch, repaired a rear main seal leak and replaced the crank shaft position sensor as an opportunity while doing the work. As a precaution. I checked the spark plug wires for looseness and after doing that the fault didn’t come back. The truck ran well until today. The fault didn’t show up but it still ran poorly. More like a cough. I am going to take it to a shop and have it put on an analyzer tomorrow and hopefully I can get it repaired. If not, then I’ll either be late or not attend. Any input is appreciated.