my buddy put a set of ngk non platinums in his car when he did the tuneup and replaced the upper and lower intake gaskets,well now that its back together she is running real sluggish,would the ngks have something to do with that?never even considered putting them in my car so idk.ill always run autolights.lmk what ya think..thanks

 

I would be looking for a vacuum leak considering he replaced the plenum gasket. Also you say he did a tune up, was the timing adjusted (properly) and was the spout connector re-installed?

 

Nothing wrong with the NGK's unless they where gapped wrong.

Look into what PJC Racing said. Might have a vacuum leak and/or since the upper and lower intake gaskets where replaced I am assuming the lower intake came off which in turn means the dissy was removed more than likely. Make sure the timing is correct.