have posted on here before, had misfire in 6, changed plug, coil, injector and i think the misfire may have finally been solved, but my mechanic, also father n law, did a smoke test to check for leaks becasue the truck still rough idles on cold start only for about 35 seconds. he said it has small leak in 8 cylindar. what exactly does that mean? head gasket leak?

 

also on the scanner when running live data it shows that my stft s1 b1 and stft s2b2 are both at 99.4 which i believe is lean. can the leaness be from the intake or head gasket leak?