chance olson

Hello Everyone I'm working on a 97 GMC suburban with a 5.7l vortec. it has a P0300 random misfire code that i cannot figure out and is primarily in cylinder #6 what I've done -Compression is roughly 160 -replaced spark plugs/ wires -replaced cap and rotor -replace spider injector with upgraded unit from ac delco -replaced fuel filter -pulled distributor to check gear, nothing wrong and check position with scanner afterwards -pulled valve cover, push rods and valves all move (not measured, but nothing appears broke) -spraying an brake clean into the intake causes the engine to run smooth and stop misfiring/ misfire goes away at 3000rpms (watching reading on scan tool for misfires) At this point I'm thinking a hydraulic lifter, or an issue between the spider injector and computer or computer it self