Dont know what it is, but when i hit 5000-5500 rpms, engine sounds like its missing really bad, or sputtering...dont know what it is..just had engine rebuilt, and everything is new basically. any ideas? valves have been adjusted perfect

 

I thought a faulty MAP sensor can cause the engine to misfire badly at about 6k rpm.

 

sweet..i'lll try cleaning it tmw before i buy one

 

check fuel, spark, and timimg.

 

timing is right on que, and might need to change plugs...